Electrician TT – 1st Year (set 2)By pulak.univ / February 3, 2024 Welcome to your Electrician TT - 1st Year (set 2) 1. Which device converts sunlight into electrical energy? Photo voltaic cell Liquid crystal diode Light emitting diode Light dependent resistor None 2. Which law secondary cell works? Lenz’s law Joule’s law Faradays laws of electrolysis Faradays laws of electromagnetic induction None 3. What is the formula to calculate the Mass deposited during electrolysis? M = it gm M = zit gm M = it/z gm M = z/it gm None 4. How the capacity of batteries is specified? Volt Watt Volt Ampere Ampere hour None 5. What is the name of defect that bending of plates in secondary cells? Buckling Local action Partial short Hard sulphation None 6. What is the unit of electric charge? Volt Watt Ampere Coulomb None 7. What is the output voltage of lithium cell? 1.2 V 1.5 V 1.8 V 2.5 V None 8. What is the method of charging if the battery is to be charged for short duration at higher rate? Initial charge Boost charge Trickle charge Freshening charge None 9. Which electrolyte used in carbon zinc dry cells? Dilute sulphuric acid Ammonium chloride Potassium hydroxide Concentrated hydrochloric acid None 10. Which effect causes by passing electric current in liquids? | Heating Lighting Magnetic Chemical None 11. Which material is used to make negative plates in lead acid battery? Lead dioxide Sponge lead Lead peroxide Lead sulphate None 12. Which technique is used to control the corrosion of a metal surface? Anodic protection Cathodic protection Electrolytic protection Electrostatic protection None 13. Which cell is most often used in digital watches? Voltaic Lithium Mercury Silver oxide None 14. What is the effect if one cell is connected with reverse polarity in a parallel combination circuit? Voltage become zero Become open circuit Will get short circuited No effect will function normally None 15. What is the function of fine selector switch in battery charger? Selection of current rating Selection of charging time Selection of voltage range Selection of charging method None 16. What is the effect on output power with respect to temperature in solar cells? No effect on change in temperature Increases with increase in temperature Decreases with increase in temperature Decreases with decrease in temperature None 17. What purpose the hydrometer is used during charging of battery? Determine the AH capacity Assess the battery voltage level Assess the discharge level of battery Determine the specific gravity of electrolyte None 18. What is the formula for Faraday’s first law of electrolysis? M = Z/it M = Zit M = it/ Z M = Zt/i None 19. Which is used as an electrolyte in lead acid battery? Hydrochloric acid Ammonium chloride Potassium hydroxide Diluted sulphuric acid None 20. What is the total voltage of the circuit? Add description here! 1.5 Volt 6.0 Volt 7.5 Volt 9.0 Volt None 21. What is the outcome at the positive plate, after the chemical reaction in lead acid battery during charging? Sponge lead(Pb) Lead peroxide(PbO2) Lead sulphate(PbSO4) Lead sulphate + water None 22. Why the vent plug is kept open during charging of a battery? To escape the gas freely To allow oxygen enter inside To check the level of electrolyte To check the colour changes in the plates None 23. In which method the battery is charged at low current for long period? Rectifier method Trickle charging method Constant current method Constant potential method None 24. How the hard sulphation defect in lead acid battery can be rectified? Changing with new electrolyte Replacing with new electrodes Recharging the battery for a longer period at low current Recharging the battery for short period at high curren None 25. Which material is used as cathode (-ve) electrode in silver oxide battery? Zinc Copper Carbon Silver oxide None 26. What is the Electro Chemical Equivalent (ECE) of silver? 0.001182 mg/coulomb 0.01182 mg/coulomb 0.1182 mg/coulomb 1.1182 mg/coulomb None 27. What is the purpose of separator in lead acid battery? To provide a path for electrolyte To hold the positive and negative plate firmly To avoid short in between the positive and negative plates To keep positive and negative plate in a sequence array None 28. Which instrument is used to measure the specific gravity of electrolyte in lead acid battery? Barometer Hydrometer Anima meter High rate discharge tester None 29. Which type of inverter circuit? Add description here! Driven inverter SCR used inverter Single transistor inverter Two winding transformer inverter None 30. What is the effect of buckling defect in a lead acid battery? Bending of the electrodes Reducing the strength of electrolyte Making short between the electrodes Increasing the internal resistance None 31. What is the total output voltage of the circuit? Add description here! 0 V 1.5 V 3.0 V 4.5 V None 32. Which is used as a positive electrode in a dry cell? Zinc Carbon Copper Lithium None 33. What happen to the terminal voltage of a cell if load increases? Increases Decreases Falls to zero Remains same None 34. How local action defect is prevented in voltaic cell? By connecting cells in series By using a depolarizing agent By connecting cells in parallel By amalgamating the zinc plate None 35. What does the letter Z indicate in the formula M=Z/it Time in seconds E.C.E of electrolyte Amount of current in Amp Mass deposited in grams None 36. What is the Electro Chemical Equivalent (ECE) of copper? 0.329 mg / coulomb 0.329 g/ coulomb 1.1182 mg / coulomb 1.1182 g/ coulomb None 37. Which is the cause for buckling defect in lead acid battery? Overcharging or over discharging Charging with low rate for short period Formation of sediments falling from the plate Battery is kept in discharged condition for long period None 38. Which apparatus is used to check the charging condition of voltage in battery? Voltmeter Multimeter Hydrometer High rate discharge tester None 39. Which part is losing electron during electrolysis? Cathode Anode Electrolyte Seperator None 40. How the conduit pipes are specified Length in metre Wall thickness in mm Inner diameter in mm Outer diameter in mm None 41. What is the fusing factor for rewireable fuse? 1.1 1.4 2.1 2.5 None 42. What is the purpose of underwriter’s knot for pendent holder connection? Avoid loose connections Increase mechanical strength Prevent excessive cap cover pressure Reduce the strain from the terminals of accessories None 43. What is the type of fuse? Knife edge cartridge fuse High rupturing capacity fuse Ferrule contact cartridge fuse Diazed screw type cartridge fuse None 44. What is the name of electrical accessory? Bracket holder Edison screw type holder Angle swivel lamp holder Goliath Edison screw lamp holder None 45. Goliath Edison screw lamp holder Link Fuse Pull switch Plug and socket None 46. Which type of load is protected by the L-series MCB Motors Geyser Hand tools Air conditioner None 47. Which type of switch is used in the circuit? One-way switch Two-way switch Intermediate switch Multiposition switch None 48. What is the effect of low current rated cable used to connect higher current load? Voltage drop increases Load current increases Voltage drop decreases Cable damage due to heat None 49. What is the name of the conduit accessory? Solid bend Solid elbow Inspection Bend Inspection elbow None 50. How many two way switches with intermediate switch are used to control one lamp from three different places? 1 2 3 4 None 51. What is the advantage of concealed wiring? Easy to maintain Less voltage drop High insulation resistance Protection against moisture None 52. What is the name of the diagram? Add description here! Installation plan Layout diagram Wiring diagram Circuit diagram None 53. What is the fusing factor for high repturing capacity fuses (HRC)? 1.0 1.1 1.4 1.7 None 54. Which type of relay can be operated at both A.C and D.C? Ferred relay Thermal relay Impulse relay Dry reed relay None 55. What is the name of the accessory used in electrical appliances? Add description here! 2 Pin plug Three pin plug Iron connector with direct entry Flat connector with side entry None 56. What is the name of the accessory symbol? Add description here! Bell push switch Two way switch One way switch two poles Multi position switch single pole None 57. What is the purpose of the flexible cords in domestic wiring? Concealed wiring Permanent connection Run cable through holes in ceiling Connection transportable appliances None 58. Which type of circuit breaker is used above 100 A current rating? Miniature Circuit Breaker (MCB) Earth Leakage Circuit Breaker (ELCB) Moulded Case Circuit Breaker (MCCB) Residual Current Circuit Breaker (RCCB) None 59. What is the purpose of tin coating on copper fuse wire? Withstand high temperature Increase the fusing factor Prevent oxidation of copper wire Increase the mechanical strength None 60. What is the name of the four insulated conductors group? Pair Core Quad Layer None 61. How many two way switches are required in godown wiring circuit to control four lamps 2 3 4 5 None 62. Which type of transformer is used for high frequency application? Ring core transformer Ferrite core transformer Silicon steel core transformer Grain oriented core transformer None 63. What is the relationship between primary voltage (E1, V1) and secondary voltage (E2, V2) in a ideal transformer? E1= V1 and E2 = V2 E1 > V1 and E2 > V2 E1 < V1 and E2 < V2 E1 = V2 and E2 = V1 None 64. What is the function of conservator in transformer? Prevents the moisture entry Transfers the heat to atmosphere Allows to release internal pressure Allows expansion of oil level due to load variation None 65. Which loss of transformer is determined by short circuit test? Copper loss Windage loss Hysteresis loss Eddy current loss None 66. Calculate the voltage regulation in percentage of the transformer if the no load voltage is 240 volt and full load voltage is 220 volt? 7.2 % 8.3 % 8.71% 9.09% None 67. What is the purpose of using laminated core in transformer? Reduce copper loss Reduce hysteresis loss Reduce mechanical loss Reduce eddy current loss None 68. What is the cooling method of transformer? Oil natural cooling Oil natural air forced cooling Oil forced air forced cooling Oil natural water forced cooling None 69. What is the condition for obtaining maximum efficiency from transformer? Copper loss > Iron loss Copper loss < Iron loss Copper loss = Iron loss Copper loss =Eddy current loss None 70. What is the function of top float switch of buchholz relay in transformer? Activate in moisture presence Activate at overloading condition Activate at open circuit condition Activate at high temperature condition None 71. Why the core of current transformer is having low reactance and low core losses? To minimise the burden To maintain constant output To prevent high static shield To minimise the error in reading None 72. How the error in reading of a potential transformer can be reduced? Using thin laminated core Providing long magnetic path Using high flux density material Providing good quality core material None 73. Why the load is disconnected before the OFF load tap changing operation? To disconnect the tappings from neutral point To disconnect the moving contact of the diverter To avoid heavy sparking at the contact points To provide an electrical isolation for the windings None 74. What is the name of the part in power transformer? Breather Tap charger Explosion vent Buchholz relay None 75. Which condition is absolutely essential for parallel operation of two transformers? Nature of load Type of cooling Phase sequence Class of insulation used None 76. Which construction technique is used to reduce copper loss in larger transformers? Use of laminated core By reducing core thickness By using grain oriented core Use stepped core arrangement None 77. What is the name of transformer? Air core transformer Iron core transformer Ring core transformer Ferrite core transformer None 78. Which transformer is used to measure high voltage installations? Pulse transformers Ignition transformers Potential transformers Constant voltage transformers None 79. How does the moisture is controlled in breather fitted on power transformers? | Using silica gel Using transformer oil Using sodium chloride Using ammonium jelly None 80. Which power loss is assessed by open-circuit test on transformer? Hysteresis loss only Eddy current loss only Copper loss Core loss None 81. Which is determined by the crackle test of transformer oil? Acidity Moisture Viscosity Dielectric strength None 82. Which material is used to make core of power transformer? Soft iron Rolled steel Copper alloy Cold rolled grain oriented None 83. What is the name of transformer? Auto transformer Core type transformer Shell type transformer Audio frequency transformer None 84. What is the purpose of providing explosion vent in a power transformer? Air releasing Heat releasing Pressure releasing Moisture releasing None 85. What is the function of buchholz relay in power transformer? Protection from high temperature Protection from moisture entering in oil Protection from pressure loading in tank Protection from both overloading and short circuit None 86. Why primary of potential transformer is wound with thin wire and large number of turns? To offer high inductance To obtain required voltage ratio To regulate the primary current To stabilise input and output voltage None 87. Why distribution transformers are normally connected as primary in delta and secondary in star? To avoid overloading To maintain constant voltage To reduce transformer losses To reduce transformer losses None 88. Which type of emf is induced in an ideal two winding transformer? | Self induced emf Mutually induced emf Statically induced emf Dynamically induced emf None 89. How to determine copper loss in a transformer? Ratio test Impulse test Short circuit test Open circuit test None 90. Why ferrite core is used in radio receivers? To reduce the constant losses To reduce electric interference To increase the quality of sound To increase the efficiency of receivers None 91. What is the advantage of stepped core arrangement in larger transformers? Minimizes copper use Reduces hysteresis loss Reduces eddy current loss Reduces the space for core None 92. Which material is used in breather to prevent moisture entering in the transformer oil? Silica gel Sodium chloride Ammonium chloride Charcoal and salt mixture None 93. What is the disadvantage of auto transformer? More losses Heavier in weight Poor voltage regulation Cannot isolate the secondary winding None 94. Which cooling method is used in pole mounting distribution transformer? Air natural Oil natural air blast Oil forced air forced Oil natural air natural None 95. What is the composition of steel and silicon steel in transformer core? Steel 97% and silicon 3% Steel 95% and silicon 5% Steel 93% and silicon 7% Steel 90% and silicon 10% None 96. What is the purpose of tap changing in power transformers? Change voltage ratio in distribution Change voltage ratio in distribution Maintain secondary voltage constant Load the transformer for maximum efficiency None 97. Which material is used to make heating element? Silver Copper Nichrome Aluminium None 98. What is the name of the part of electric iron? Sole plate Pressure plate Mica insulation Asbestos sheet None 99. What is the function of stirrer motor in microwave oven? Draws cooling air inside Spreads the heat uniformly Exhausts the hot air outside Revolves and reflects the electromagnetic energy None 100. None 101. What is the purpose of U bend marked as X in geyser? Prevents draining of water Avoids the forming of scales Reduces the pressure of outlet pipe Restricts the air locking inside the tank None 102. Which type of A.C single phase motor is used in food mixer?Which type of A.C single phase motor is used in food mixer? Universal motor Repulsion motor Split phase motor Shaded pole motor None 103. Which is the position for maximum output of the heater? Position 1 Position 2 Position 3 Position 4 None 104. Which formula is used to calculate the heat generated as per Joules law? Heat generated = IRT/ J CAL Heat generated = |2RT/J CAL Heat generated = IR2T/Jcal Heat generated = (IR)2 T/Jcal None 105. Calculate the heat generated in a electric heater of 1000 watt, 240 volt, worked for 5 minutes? 70.5 kilo calories 71.0 Kilo calories 71.6 Kilo calories 72.1 Kilo calories None 106. What is the purpose of protection grooves at various places in a heater base plate? Radiate the heat properly Retain the heating element firmly Place the vessels firmly on heater plate Protect the heating element from damage None 107. What is the purpose of sole plate in electric kettle? Acts as a balancing weight Acts as an insulator for element Protect the kettle base from damage Keep the element in close contact with container None 108. What is the magnetron tube filament voltage used in microwave oven? 1.5 V A.C 2.0 V A.C 3.0V A.C 3.2V A.C None 109. What is the fault in a food mixer if it runs intermittently? Worn out brushes Armature coil open Defective commutator Field winding partially short None 110. What is the defect in a single phase pump motor if it runs with slow speed? Defective capacitor Open starting winding Short in starting winding Short in running winding None 111. What is the function of neutral path in AC supply system for appliances? Provides current return path Provides level constant Reduces voltage drop in wiring Maintains load current constant None 112. What is the function of magnetron tube in a microwave oven? Amplifies the microwave signal Changes the polarity every half cycle Oscillate and produce cooking frequency Converts microwave energy to electrical energy None 113. Which type of motor is used in the wet grinder? Universal motor Capacitor start induction run motor Capacitor start capacitor run motor None 114. What is the name of the circuit? Electronic fan regulator Electronic voltage multiplier Electronic voltage stabilizer Electronic triggering circuit of SCR None 115. What is the maximum permissible load for a power sub circuit as per I.E rules? 800 Watt 1500 Watt 2000 Watt 3000 Watt None 116. Which location the service connection supply leads to be connected at consumer main board? IC cut out Main switch Energy meter Distribution board None 117. What is the type of test in domestic wiring installation? Add description here! Polarity test Continuity (or) open circuit test Insulation resistance test between conductors Insulation resistance test between conductors and earth None 118. What is the permissible leakage current in domestic wiring installation? 1/5 x Full load current | 1/50 x Full load current 1/500 x Full load current 1/5000 x Full load current None 119. Which formula is used to calculate the diversity factor? None 120. Which instrument is used to test new domestic wiring installation? Multimeter Megger Shunt type ohmmeter Series type ohmmeter None 121. What is the type of test in the wiring installation? Add description here! Polarity test Open circuit test Insulation resistance test between conductors Insulation resistance test between conductors and earth None 122. Where system earthing is done? Generating station Electroplating installation Small industrial installation Domestic wiring installation None 123. What is the test to be carried out by using megger? Polarity test Insulation resistance test Earth electrode resistance test Earth conductor continuity test None 124. What is the reason of lamp glowing dim and motor running slow in a domestic wiring circuit? Open circuit in the neutral line Short circuit between conductors High value series resistance fault Open circuit in the earth conductor None 125. Which wiring installation the System earthing is to be done? Substations Godown wiring Domestic wiring Commercial wiring None 126. Which method of earth resistance measurement is illustrated? Fall of current Fall of potential Current dividing Potential dividing None 127. How to control harmonic distortions in neutral connections as per IE rule? Earthing through impedance Providing by plate earthing Increasing conductor size Providing parallel earthing None 128. What is the function of current reverser in earth resistance tester? Converts A.C. into D.C Reverses the polarity of D.C Changes D.C. supply into A.C supply Reverses the direction of rotation of the generator None 129. What is the advantage of stranded conductor over solid conductor? Cost is less More flexible Less voltage drop More insulation resistance None 130. How the earth resistance can be reduced? Providing double earthing Reducing the pit depth for earthing Increasing the length of the electrodes Decreasing the length of the electrodes None 131. What is the reason for supplying AC to the electrodes for measuring earth resistance? Provide electrostatic shield Protect the coils in the meter Reduce the value of current in the meter Avoid the effect of electrolytic emf interference None 132. Why the pointer is not stable at zero on the scale as the megger is not in use? It is not having controlling Torque Provided with air friction damping The deflecting torque is directly proportional to the current The deflecting torque is directly proportional to the square of the current None 133. Which is proportional for the deflection of ohmmeter needle in earth resistance tester? Current in current coil Current in potential coil Speed of the handle rotation Ratio of the current in two coils None 134. Which principle the earth resistance tester works? Self induction Mutual induction Fall of potential method Fleming’s left hand rule None 135. Why system earthing is different in utilization than equipment earthing? It protects human only It protects from all circuit faults It is associated with current carrying conductors It is connected to the non current carrying metal work None 136. What is the effect if a person receives a shock current of 20 mA? No sensation Painful shock Heart convulsions Become unconscious None 137. Which electrical equipment L series type MCB’s are used? Geysers Locomotives Halogen lamps Air conditioners None 138. What is the megger reading in a dead short wiring installation? 0 M OHM 1 M OHM 500 M OHM Infinity None 139. What is the advantage of crimping? Gives neat apperance Reduce load current Avoid loose connections Easy to replace None 140. What is the S.I unit of luminous intensity? Lux Lumen Candela Steradian None 141. What is the working temperature of filament lamp 1500°C 1800°C 2000°C 2300°C None 142. Which material is coated in tungsten electrode of a fluorescent tube lamp? Silver oxide Phosphor powder Fluorescent powder Barium and stroatium oxide None 143. Which position MB type high pressure mercury vapour lamps are operated? Vertical Inclined Horizontal Any position None 144. What is the function of leak transformer in high pressure sodium vapour lamp circuit? Reduce the starting current Reduce the working voltage Increase the working voltage Ignite the high voltage initially None 145. How stroboscopic effect in industrial twin tube light fitting is reduced? Connecting capacitor parallel to supply Connecting capacitor in series with supply Connecting capacitor in series with one tube light Connecting two capacitors in series to each tube light None 146. What is the current carrying capacity of flasher, if the current is 100 mA in each row? Add description here! 50 mA 100 mA 200 mA 300 mA None 147. Which term refers that the flow of light into a plane surface? Lumen Illuminance Luminous flux Luminous intensity None 148. What is the purpose of ignitor in high pressure sodium vapour lamp circuit? Decreases the starting current Increases the running voltage Decreases the running current Generates high voltage pulse at starting None 149. Which type of light fitting design has free from glare? Semi direct type Semi indirect type Direct lighting type Indirect lighting type None 150. Why the outer tube of a high pressure metal halide lamp made of boro silicate glass? Increase the lighting effect Withstand heavy temperature Withstand atmospheric pressure Reduce the ultra violet radiation from lamp None 151. What is the term refers luminous flux given by light source per unit solid angle? Lumen Candela Illuminance Luminous intensity None 152. What is the unit of luminous flux? Lux Lumen Candela Lumen/m square None 153. What is the unit of luminous efficiency? Lux Lumen Lumen/m2 Lumen/watt None 154. How the rate of evaporation in a vacuum bulb is reduced? Filling inert gas Producing arc in bulb Reducing filament resistance Increasing filament resistance None 155. What is the main advantage of coiled coil lamp? High melting point Higher light output Low operating voltage Low power consumption None 156. What is the name of the reflector? Mirror type Soft light type Parabolic type Dispersive type None 157. What is the name of light? Spot light Bulk light Flood light Flash light None 158. Which device provides ignition voltage and act as choke in a HPSV lamp? Arc tube Sodium vapour Leak transformer High pressure aluminium oxide None 159. What is the name of lamp? MAT type MV lamp HP metal halide lamp MB type HPMV lamp MA type HPMV lamp None 160. Which type of lighting system is used for flood and industrial lighting? Direct lighting Indirect lighting Semi-direct lighting Semi-indirect lighting None 161. Which is the cold cathode lamp? Halogen lamp Neon sign lamp Fluorescent lamp Mercury vapour lamp None 162. Which force is required to move the pointer from zero position in an indicating instrument? Controlling force Deflecting force Air friction damping Eddy current damping None 163. Which is the position to use the instrument provided with gravity control? Any position Vertical position Inclined position Horizontal position None 164. What is the name of the scale? Linear scale Coarse scale Extended scale Non-linear scale None 165. Which error is caused by the incorrect position of instrument reading? Device error Human error Influence error Switching error None 166. Which instrument is used to measure one ohm and below one ohm resistance value accurately? Megohm meter Multimeter (analog) Shunt type ohm meter Series type ohm meter None 167. What is the purpose of the 3rd terminal provided in a advanced megohm meter? Get higher ohmic values Pass the excess voltage to ground Pass the excess current to ground Get accurate readings without oscillation None 168. What is the name of the shunt resistance material? Copper Eureka Nichrome Manganin None 169. What is the reason for the moving coil meter having uniform scale? Deflecting torque is directly proportional to the current Deflecting torque is inversely proportional to the current Deflecting torque is inversely proportional to the square of the current Deflecting torque is directly proportional to the square of the current None 170. Which error if the energy meter disc rotating continuously on no load? Speed error Phase error Friction error Creeping error None 171. What is the effect on CT if its secondary is kept open? | CT primary burns out Volt ampere capacity reduces Volt ampere capacity increases CT secondary winding burns out None 172. What is the purpose of variable resistor connected across shunt type ohm meter? Avoid draining of battery Minimize the error in reading Adjust the current to safe value Adjust the pointer to zero adjustment None 173. Which material is used to make control spring in measuring instruments? Steel Silver Tinned copper Phosphor bronze None 174. Which electrical effect that the single phase energy meter works? Heating effect Induction effect Chemical effect Electrostatic effect None 175. Which is the position to use the instrument provided with spring control? Any position Vertical position only Inclined position only Horizontal position only None 176. What is the name of meter? AC multirange ammeter DC multirange voltmeter AC and DC multirange ammeter AC and DC multirange voltmeter None 177. Which instrument is an example of an integrating instrument? AC voltmeter DC voltmeter Energy meter Tangent galvanometer None 178. How the creeping error is controlled in energy meter? By reducing rated voltage By increasing the inductive load By adjusting the brake magnet position By drilling two holes diametrically opposite on disc None 179. Why the scale of the moving iron instrument is having un-uniform scale? Deflecting force is directly proportional to the Current Deflecting force is inversely proportional to the Current Deflection of force is directly proportional to the square of the Current Deflection force is inversely proportional to the square of the Current None 180. Which source of measuring error is caused by the effect of magnetic fields? Device error Human error Influence error Switching error None 181. Which type of wattmeter? Three element 4 wire wattmeter Two element 3 phase wattmeter Three element 3 phase wattmeter Three phase two element with C.T & P.T None 182. Which type of instrument is used with air friction damping? Moving coil instrument Moving iron instrument Induction type instrument Dynamo meter type instrument None 183. Which type of energy meter works with netural connection? Three phase two element Three phase three element Single phase single element Three phase two element with CT & PT None 184. What is the type of frequency meter? Weston type Ratio meter type Electro dynamic type Mechanical resonance type None 185. What is the unit of sensitivity in instruments? Volt / ohm Ohm / volt Ohm metre Ohm / metre None 186. Why two straight holes are provided in the aluminium disc in energy meter? To reduce the disc weight For power factor correction To prevent the flux leakage To arrest the creeping error None 187. What is the name of the instrument? Absolute instrument Indicating instrument Recording instrument Integrating instrument None 188. Why damping force is required in a moving coil instrument? Makes the needle movement faster Helps the deflecting force to act fast Brings the needle to its zero position Arrests the needle without oscillations None 189. What is the function of soft iron core in a moving coil instrument? | Strengthens the deflection force Controls the needle’s movement Provides meter with maximum sensitivity Provide uniform distribution of magnetic flux in air gap None 190. Which parameter is the cause for loading effect on measuring instruments? Low accuracy High sensitivity Low sensitivity Low influence error None 191. Name the type of instrument? Attraction type moving iron | Repulsion type moving iron Permanent magnet moving coil Dynamo meter type moving coil None 192. Which meter is used to measure revolution per minute of a motor? Tachometer Energy meter Ampere hour meter Centre zero ammeter None 193. How to identify the moving iron type instrument? No terminal marking Terminal marked (+) only One terminal coloured red Terminal marked (+) and (-) None 194. Which is an absolute instrument? Ammeter Volt meter Energy meter Tangent galvanometer None 195. Which force produces movement of pointer in an indicating instrument? Damping force Deflecting force Repulsion force Controlling force None 196. What is the function of integrating instrument? Displays the quantity Indicates the quantity Registers the quantity Measures the quantity None 197. Which position an instrument using gravity control reads accurately? Any position Vertical position Inclined position Horizontal position None 198. Which quantity is measured by an electrodynamo type instrument? Power Current Voltage Resistance None 199. How to achieve maximum accuracy in measurement using analog instrument? Keep low input impedance Keep high input impedance Use short connecting leads Provide correct damping system None 200. Calculate the value of shunt resistance required to measure 10 mA with one mA meter? 3 ohm 30 ohm 0.3 ohm 300 ohm None 201. Which material is used to make heating element? Silver Copper Nichrome Aluminium None 202. What is the name of the part of electric iron? Sole plate Pressure plate Mica insulation Asbestos sheet None 203. What is the function of stirrer motor in micro wave oven? Draws cooling air inside Spreads the heat uniformly Exhausts the hot air outside Revolves and reflects the electromagnetic energy None 204. What is the purpose of U bend marked as X in geyser? Prevents draining of water Avoids the forming of scales Reduces the pressure of outlet pipe Restricts the air locking inside the tank None 205. Which type of A.C single phase motor is used in food mixer? Universal motor Repulsion motor Split phase motoR Shaded pole motor None 206. Which is the position for maximum output of the heater? Position 1 | Position 2 Position 3 Position 4 None 207. Which formula is used to calculate the heat generated as per Joules law? Heat generated = IRT / J caL Heat generated = I2RT / J ca Heat generated = IR2T / J cal Heat generated = (IR)2 T / J cal None 208. Calculate the heat generated in a electric heater of 1000 watt, 240 volt, worked for 5 minutes? 70.5 Kilo calories 71.0 Kilo calorie 71.6 Kilo calories 72.1 Kilo calories None 209. What is the purpose of protection grooves at various places in a heater base plate? Radiate the heat properly | Retain the heating element firmlY Place the vessels firmly on heater plate Protect the heating element from damage None 210. What is the purpose of sole plate in electric kettle? Acts as a balancing weight Acts as an insulator for element Protect the kettle base from damage Keep the element in close contact with container None 211. What is the magnetron tube filament voltage used in microwave oven? 1.5 V A.C 2.0 V A.C 3.0 V A.C 3.2 V A.C None 212. What is the fault in a food mixer if it runs intermittently? Worn out brusheS Armature coil open Defective commutatoR Field winding partially short None 213. What is the defect in a single phase pump motor if it runs with slow speed? Defective capacitor Open starting winding Short in starting winding Short in running winding None 214. What is the function of neutral path in AC supply system for appliances? Provides current return path Provides voltage level constant Reduces voltage drop in wiring Maintains load current constant None 215. What is the function of magnetron tube in a microwave oven? Amplifies the microwave signal Changes the polarity every half cycle Oscillate and produce cooking frequency Converts microwave energy to electrical energy None 216. Which type of motor is used in the wet grinder? Universal motor Repulsion motor Capacitor start induction run motor Capacitor start capacitor run motor None 217. What is the name of the circuit? | Electronic fan regulator Electronic voltage multiplier Electronic voltage stabilizer Electronic triggering circuit of SCR None 218. Which type of transformer is used for high frequency application? Ring core transformer Ferrite core transformer Silicon steel core transformer Grain oriented core transformer None 219. What is the function of conservator in transformer? Prevents the moisture entry Transfers the heat to atmosphere Allows to release internal pressure | Allows expansion of oil level due to load variation None 220. Which loss of transformer is determined by short circuit test? Copper loss Windage loss Hysteresis loss Eddy current loss None 221. Calculate the voltage regulation in percentage of the transformer if the no load voltage is 240 volt and full load voltage is 220 volt? 7.2 % 8.3 % 8.71 % 9.09 % None 222. What is the purpose of using laminated core in transformer? Reduce copper loss Reduce hysteresis loss Reduce mechanical loss Reduce eddy current loss None 223. What is the cooling method of transformer? Oil natural cooling Oil natural air forced cooling Oil forced air forced cooling Oil natural water forced cooling None 224. What is the condition for obtaining maximum efficiency from transformer? Copper loss > Iron loss Copper loss < Iron loss Copper loss = Iron loss Copper loss =Eddy current loss None 225. What is the function of top float switch of buchholz relay in transformer? Activate in moisture presence Activate at overloading condition Activate at open circuit condition Activate at high temperature condition None 226. Why the core of current transformer is having low reactance and low core losses? To minimise the burden To maintain constant output To prevent high static shield To minimise the error in reading None 227. How the error in reading of a potential transformer can be reduced? Using thin laminated core Providing long magnetic path Using high flux density material Providing good quality core material None 228. Why the load is disconnected before the OFF load tap changing operation? To disconnect the tappings from neutral point To disconnect the moving contact of the diverter To avoid heavy sparking at the contact points To provide an electrical isolation for the windings None 229. What is the name of the part in power transformer? Breather Tap charger Explosion vent Buchholz relay None 230. Which condition is absolutely essential for parallel operation of two transformers? Nature of load Type of cooling Phase sequence Class of insulation used None 231. Which construction technique is used to reduce copper loss in larger transformers? Use of laminated core By reducing core thickness By using grain oriented core Use stepped core arrangement None 232. None 233. What is the name of transformer? Air core transforme Iron core transformer Ring core transformer Ferrite core transformer None 234. Which transformer is used to measure high voltage installations? Pulse transformers Ignition transformers Potential transformers Constant voltage transformers None 235. How does the moisture is controlled in breather fitted on power transformers? Using silica gel Using transformer oil Using sodium chloride | Using ammonium jelly None 236. Which power loss is assessed by open-circuit test on transformer? Hysteresis loss only Eddy current loss only Copper loss Core loss None 237. Which is determined by the crackle test of transformer oil? Acidity Moisture Viscosity Dielectric strength None 238. Which material is used to make core of power transformer? Soft iron Rolled steel Copper alloy Cold rolled grain oriented None 239. What is the purpose of providing explosion vent in a power transformer Air releasing Heat releasing Pressure releasing Moisture releasing None 240. What is the function of buchholz relay in power transformer? Protection from high temperature Protection from moisture entering in oil Protection from pressure loading in tank Protection from both overloading and short circuit None 241. Why primary of potential transformer is wound with thin wire and large number of turns? To offer high inductance To obtain required voltage ratio To regulate the primary current To stabilise input and output voltage None 242. Why distribution transformers are normally connected as primary in delta and secondary in star? To avoid over loading To maintain constant voltage To reduce transformer losses To easy distribution of 3 phase 4 wire system None 243. Which type of emf is induced in an ideal two winding transformer? Self induced emf Mutually induced emf Statically induced emf Dynamically induced emf None 244. How to determine copper loss in a transformer? Ratio test Impulse test Short circuit test Open circuit test None 245. Why ferrite core is used in radio receivers? To reduce the constant losses To reduce electric interference To increase the quality of sound To increase the efficiency of receivers None 246. What is the advantage of stepped core arrangement in larger transformers? Minimizes copper use Reduces hysteresis loss Reduces eddy current loss Reduces the space for core None 247. Which material is used in breather to prevent moisture entering in the transformer oil? Silica gel Sodium chloride Ammonium chloride Charcoal and salt mixture None 248. What is the disadvantage of auto transformer? More losses Heavier in weight Poor voltage regulation Cannot isolate the secondary winding None 249. Which cooling method is used in pole mounting distribution transformer? Air natural Oil natural air blast Oil forced air forced Oil natural air natural None 250. What is the composition of steel and silicon steel in transformer core? Steel 97% and silicon 3% Steel 95% and silicon 5% Steel 93% and silicon 7% Steel 90% and silicon 10% None 251. Cells are connected in parallel to: increase the internal resistance increase the output e.m.f. ncrease the current capacity decrease the current capacity None 252. Cells are connected in series to decrease the output e.m.f. increase the output e.m.f. decrease the internal resistance increase the current capacity. None 253. The mass of material deposited over an electrode is: proportional to voltage proportional to time only proportional to current only proportional to quantity of electricity and E.C.E None 254. In electroplating, the positive electrode is called: cathode terminal anode ion trap None 255. The condition of electrplyte in a battery is measured in terms of: current value specific gravity acid contents voltage output None 256. In a primary cell, the local action can be rectified by: charging the cell amalgamating the zinc electrode with mercury using a cell for few minutes only making a dry cell None 257. The function of a dry cell is to convert: chemical energy to mechanical energy chemical energy to electrical energy electrical energy into mechanical energy electrical energy into magnetic energy None 258. Polarisation in a primary cell can be removed by: coating the electrodes of the cell chemical action discharging the cell disposing the cell None 259. The two main defects of a primary cell are: local-action and polarisation local-action and sulphation buckling and polarisation sulphation and sedimentation None 260. An average dry cell gives an approximate e.m.f. of: 1.2 V 1.3 V 1.4 V 1.5 V None 261. Lechlanche cell is most suited for: continuous use large current requirements intermittent use large voltage requirements None 262. Cells are connected in parallel to increase the internal resistance increase the output e.m.f increase the current capacity decrease the current capacity None 263. Cells are connected in series to: decrease the output e.m.f. increase the output e.m.f decrease the internal resistance increase the current capacity. None 264. The function of depolariser in it converts the produced hydrogen Lechlanche cell is that: into water it prevents the fast chemical action on the zinc electrode it synthesizes the decomposed it absorbs the oxygen produced in the electrolyte cell None 265. Secondary cell can produce large amount of power for a : short time and can be recharged long time and can be recharged short time and can not be recharged long time and can not be recharged None 266. Gassing occurs in the process of: charging an accumulator charging a dry cell discharging an accumulator discharging a dry cell None 267. The charge condition of a secondary cell can be checked by: its terminal voltage the colour of its electrolyte the level of its electrolyte its terminal voltage and specific gravity of its electrolyte None 268. A lead-acid accumulator should be recharged when the specific gravity of its electrolyte is about: 1.18 1.15 1.35 1.25 None 269. Other types of accumulators besides the lead-acid type are: ( alkaline batteries only alkaline and solar batteries alkaline and dry batteries nickel-cadmium and nickel-iron batteries None 270. Which one of the following acts as depolariser in a dry cell? Manganese dioxide Zinc chloride Ammonium chloride Carbon powder None 271. One main advantage of a secondary cell is this that it: can be used in portable equipments ( can be recharged is compact and hence easy to transport cannot be recharged None 272. . Nickel-cadmium dry cell is becoming popular in power supplies for electronic calculators because: it has a standard shape it is dry it is rechargeable it is easily manufactured None 273. The ampere-hour capacity of a battery depends on the thickness of plates the distance between the plates the number and area of plate None 274. In order to keep the terminals of a lead acid battery free from corrosion, it is advisable to clean the terminals frequently change the battery at frequent intervals clean the terminals and to apply petroleum jelly wash the terminals with water frequently None 275. The internal resistance of a discharged is high ( is low remains the same is negative None 276. It is not desirable to leave a lead-acid battery in discharged state for a long time because: the electrolyte will attack the container the electrolyte will become weak the plates will get sulphated strongly the electrolyte will evaporate None 277. The separators in a lead-acid battery are designed to prevent the plates from: touching the electrolyte shorting together shorting with the sediments touching the container None 278. The advantage of nickel-iron cell over lead-acid cell is this that: it has a higher efficiency it needs less maintenance it is much cheaper it gives a higher e.m.f. None 279. While charging the accumulators, one should check the acid level with a lighted match shot-circuit the cell terminals to see that they are fully charged keep them in a well-venilated room connect and disconnect them with the d.c. source None 280. A lead-acid cell is rechargeable because its electrolyte is sulphuric it is a wet cell its chemical action is reversible its electrolyte has a high specific gravity None 281. A 100 Ah capacity battery should de liver a current of 8 A for approximately: 20 h 8 h 12 h 100 h None 282. When a lead-acid battery is needed to be kept idle for a long time then: overcharge the battery clean the plates with distilled water remove the electrolyte remove electrolyte and dry up the battery and store the same in a cool, dry and clean place None 283. Which one of the following is not a maintenance free battery? Ni-Cd Ni-Fe Alkaline magnesium Lead-acid None 284. The advantage of alkaline magnesium battery is high internal resistance high nominal voltage low initial cost all the three stated above None 285. As compared to lead-acid cell, the efficiency of a Ni-Fe cell is less due to lower e.m.f. smaller quantity of electrolyte higher internal resistance compactness of the cell None 286. If a battery has not been used for a long period then the same should be put on : float charge boost charge trickle charge freshening charge None 287. In order to increase the Ah capacity of a lead-acid battery --- less number of plates are to be used more number of plates are to be used height of the plates is to be decreased thickness of the plates is to be increased None 288. The state of charge / discharge of a lead-acid battery can be known by measuring the level of the electrolyte the weight of the electrolyte the specific gravity of the electrolyte any one of the above stated parameter None 289. The instrument used for measuring the S.G. of electrolyte of a lead-acid battery is called lactometer hydrometer voltmeter hygrometer None 290. The level of electrolyte in lead-acid cells should be 10 mm below the top of the plates 25 mm below the top of the plates exactly at the top of the plates 10 to 15 mm above the top of the plates None 291. The e.m.f. produced by a zinc-carbon cell is 1.2 V 1.5 V 2.0 V 1.8 V None 292. A dry cell is declared unfit for use if its output e.m.f. has remained only... of its rated value 40% 50% ) 60% 75% None 293. Cells can be classified into two categories namely cylindrical cell and rectangular cell dry cell and wet cell primary cell and secondary cell acid cell and alkali cell None 294. . In order to increase the ampere-hour rating of a battery, cells are connected in series parallel series parallel star None 295. A lead-acid battery should not be used, if it is discharged beyond the minimum value of 1.2 V per cell 1.5 V per cell 1.7 V per cell 2.0 V per cell None 296. When a secondary cell is supplying current to the load, it is said to be loading discharging unloading None 297. A discharged battery should not be tested by using high rate discharge tester voltmeter hydrometer any of the above stated instruments None 298. The current rating of a battery is given in amperes ampere-hours coulombs none of the above stated units None 299. The active material of a lead-acid cell is/are spongy lead lead peroxide dilute sulphuric acid all the above stated materials None 300. In a lead-acid battery, sulphation accurs due to keeping the battery idle for a long time trickle charging high rate discharging high rate charging None 301. The active materials of Ni-Fe cell are nickel hydroxide powdered iron and ferrous hydroxide 21% solution of caustic potash all the above stated materials None 302. During charging or discharging of a Ni Fe cell its e.m.f. remains constant water is neither formed nor absorbed corrosive fumes are produced nickel-hydroxide remained unsplit None 303. Boost charge is given to ) dead battery battery in danger of becoming over discharged during a working shift fully charged battery completely discharged battery None 304. In order to charge a 6 V battery in constant voltage charging method, the D.C. output of the charger should be 6 V 7V 8 V 9V None 305. The ratio of normal charging current to the trickle charging current is 1:2 1:10 1:20 1:100 None 306. Which type of battery is generally used in emergency lights - Primary Alkaline Lead-acid Edison None 307. Which gas is produced during charging a lead-acid battery Hydrogen Methane Oxygen Carbon dioxide None 308. The nominal e.m.f. of a Ni-Cd cell is 1.50 V 1.25 V 1.00 V 2.00 v None 309. In constant voltage battery charging method, the voltage applied across the battery is equal to the battery nominal voltage twice the battery nominal voltage 2.3 to 2.5 V per cell half the nominal voltage of the battery None 310. As compared to a lead-acid cell, the efficiency of a nickel-iron cell (Edison cell) is less due to the lower e.m.f. smaller quantity of electrolyte higher internal resistance compactness of the cell None 311. The disadvantage of constant current battery charging method is its charge efficiency is low it takes comparatively long time to charge a battery fully in it, per cell charging voltage should no exceed 2.3 to 2.5 volts. all the three problems stated above None 312. Which one of the following is not a maintenance free battery Ni-Cd Ni-Fe Alkaline magnesium Lead-acid None 313. Lead acid cells are used in automobiles quartz watches portable radio receivcers all the above None 314. The normal voltage of a fully charged lead acid cell is...... 1.1 V 1.5 V 2.2 V 3.0 V None 315. The relative density of the electrolyte in a lead acid battery is 1.280. This value indicates that the battery is....... fully discharged half charged three quarter charged fully charged None 316. The main purpose of lead acid battery is to store electrical energy in the form 10 A 10 A 12 V 12V The total voltage is 24 V The total voltage is zero The arrangement can be loaded upto 10 A maximum The arrangement can supply a maximum current of 20 A at 12 V None 317. Which metal is used to provide strength to the lead acid battery plates? Zinc Tin Antimony Copper None 318. The electrolyte used in a lead acid battery is.... Sulphuric acid and diluted lead diluted lead and pure water pure water and distilled water distilled water and sulphuric acid None 319. The material of the negative plate of the lead acid battery is..... Carbon rod Nickel chromium Pure lead None 320. Which electrolyte is used in lead acid battery? Potassium Hydroxide (KOH) Ammonium Chloride (NH,CL) Dilute Sulphuric acid Alkaline solution None 321. What is the minimum discharged voltage allowed after the fully discharged condition of a lead acid cell? 1.6 V 2.0 v 1.8 V 2.1 V None 322. What defect will occur in the lead acid cell, when the cell being left in a discharged condition for a long time? Partial short Buckling Hard sulphation Depolarization None 323. . Which material is applied to the terminal posts of a lead acid battery to avoid corrosion? Ammonium sulphate Silica gel Petroleum jelly Sulphur powder None 324. What is the reason to keep open the vent plugs of lead acid cell during charging? To escape the gas freely To speed up the charging rate To increase the specific gravity of the electrolyte To reduce the sulphation defect. None 325. The material of the negative plate of the lead acid battery is. Lead sulphate Carbon rod Nickel chromium Pure lead None 326. Which electrolyte is used in lead acid battery? Potassium Hydroxide Ammonium Chloride ( Dilute Sulphuric acid Alkaline solution None 327. How many lead acid cells are to be grouped for 12 V battery and by which connection? 6 cells in parallel 6 cells in series 12 cells in parallel 12 cells in series None 328. A 120 Ah capacity battery can deliver a current of 8 A for a period of...... 20 hrs ) 15 hrs 12 hrs 8 hrs None 329. A carbon-zinc cell with an internal resistance of 0.5 ohm and an EMF of 1.5 volt is loaded with an external resistor of 19.5 ohm. Calculate the current flowing through the circuit in mA? 82 mA 75 mA 72 mA 60 mA None 330. Which instrument is used to check the battery for its charging condition by measuring the voltage? Hydrometer Volt meter High rate discharge tester Multimeter None 331. The purpose of the cells are connected in parallel is to...... ) increase the voltage output increase the ampere hour capacity of the cell decrease the voltage output increase the current capacity None 332. What is the unit of the capacity of a secondary cell? volt ampere kilowatt watt hour ampere hour None 333. In electrolysis process the mass of the substances liberated (or) deposited is directly proportional to current and time voltage and resistance Internal resistance specific resistance of the plate None 334. . Battery electrolyte consists of approximately (by volume)........ 35 percent sulphuric acid and 65 percent water 65 percent sulphuric acid and 35 percent water. 65 percent nitric acid and 35 percent water. 35 percent nitric acid and 65 percent water None 335. Why are vent holes provided in wet cells? To let gases escape during charging To let gases escape during discharging To let gases escape during charging and discharging To pour electrolyte. None 336. Which type of energy transformation 92. Which instrument is used to check the battery for its charging condition by measuring the voltage? Hydrometer Voltmeter High rate discharge tester Multimeter None 337. The purpose of the cells are connected in parallel is to........ increase the voltage output increase the ampere hour capacity of the cell decrease the voltage output increase the current capacity None 338. What is the unit of the capacity of a secondary cell? volt ampere kilowatt watt hour ampere hour None 339. In electrolysis process the mass of the substances liberated (or) deposited is directly proportional to current and time. voltage and resistance Internal resistance specific resistance of the plate None 340. attery electrolyte consists of approximately (by volume)......... 35 percent sulphuric acid and 65 percent water 65 percent sulphuric acid and 35 percent water. 65 percent nitric acid and 35 percent water 35 percent nitric acid and 65 percent water. None 341. Why are vent holes provided in wet cells? To let gases escape during charging To let gases escape during discharging To let gases escape during charging and discharging To pour electrolyte None 342. A spark must not be produced when a fully charged battery is either being disconnected from a bench charger or being fitted to a vehicle because......... ) gas leaving the cells is highly explosive. gas produced by a sudden battery discharge is corrosive. spark and gas react to form dangerous fumes. spark can cause the battery polarity to reverse. None 343. The number of positive plates in a battery cell is one more than the negative plates one less than the negative plates. two less than the negative plates. two more than the negative plates. None 344. If the electrolyte level is low in a lead acid battery, the battery should be topped up with..... diluted acid clean distilled water. ) sulphuric acid and having a relative density of 1.280 an electrolyte similar to that used in the battery. None 345. The ability of a battery to supply a current similar to that required by the starter motor is tested by........ a wide scaled hydrometer a high rate discharge tester. a voltmeter scaled 0-200 V. an ammeter scaled 0-100 A None 346. The need to top up a battery at frequent intervals indicates that the battery is being overcharged charging rate is too low electrical system is shorting to earth. battery separators are not sealing the cell None 347. A maintenance-free battery... has lead-antimony plate grid. has lead-calcium plate grid does not contain acid does not contain water. None 348. With the increase of battery temperature, the specific gravity of the electrolyte increases decreases stays the same none of the above None 349. The capacity of a battery is determined by the number of plates and.... number of cells shape of plates size of plates number of separators None 350. To increase output voltage, battery cells are connected in........ series parallel series-parallel none of the above None 351. Each solar cell has a open circuit voltage having equal value to 0.55 V 0.45 Vv 0.35 V 0.25 V None 352. How many electrodes does a cell consist of? One Two Three Four None 353. While fitting the battery, observe ) electricity electrochemical electrolyte electro liquid None 354. The amount of voltage that can be obtained from a single cell of a storage battery is about.. 2V 4V 6V 8V None 355. A 12 V lead-acid battery consists of three cells in series six cells in series three cells in parallel six cells in parallel None 356. According to the 20-hour rate, a battery that can deliver 5 A for 20 hours with the cell voltage remaining above 1.75 V would be rated at.... 6 Ah 8.75 Ah 35 Ah 100 Ah None 357. . What defect will occur when the battery is over charged or discharged at a high rate? Sulphation ) Buckling Local action Partial short None 358. What is the effect on internal resistance of the cell, if the cell, it the cell is kept idle for long time? Remain the same Increased Decreased Reduced to zero None 359. What is the name of the defect occured in simple voltaic cell, due to the presence of impurities on the zinc plate? Polarisation Local action Sulphation Buckling None 360. When the current is passed through the electrolyte, what type of effect of current will produce? Magnetic effect Heating effect Chemical effect Lighting effect None 361. The mass of a substance liberated from an electrolyte by one coulomb of electricity is termed as ...... quantity of electricity electro chemical equivalent electric charge electro chemical expression None 362. What is the method of charging the battery is called, when the battery is charged at a very low rate? Rectifier method Constant current method Trickle charge method Constant voltage method None 363. Four number of cells are connected in parallel and the rating of each cell is 1.5 V and 16 Ah. What will be the "Ah" rating of this battery? 16 Ah 32 Ah 64 Ah 48 Ah None 364. The ampere hour capacity of the battery in an emergency tube light having two 20 cm tubes will be.. 4.5 Ah 6.5 Ah 10.5 Ah 12.5 Ah None 365. At the time of charging a lead acid battery which one of the harmful gas evolute? Oxygen Nitrogen Hydrogen Carbon dioxide None 366. Lines are drawn on the middle portion of caping so that the same looks beautiful the screws can drill the wires. gatiw the screws can be fitted at proper edt nollasin places in the wiring. the same remains safe. None 367. The effect of smoke, acid and alkali is negligible on: T.R.S. wire V.I.R. wire Flexible wire Jhenstib Lead sheathed wire. None 368. Tumbler switches are made of: iron rubber plastic bakelite None 369. The minimum cross-sectional area of a atm copper conductor used in a 'light and fan' sub-circuit should be: bennelg riliwe 1 mm² 2.5 mm² 2 mm² 3 mm² None 370. The minimum cross-sectional area of an aluminium conductor used in a 'light and fan' sub circuit should be: 1 mm² 2.5 mm² 1.5 mm² 4 mm² None 371. The minimum cross-sectional area of a copper conductor used in a 'power' sub ed ne5 200 circuit should be: 1.5 mm² 2.5 mm² 2.0 mm² 4.0 mm² None 372. The minimum cross-sectional area of an 9R0bn aluminium conductor used in a 'power' sub-circuit should be: 1.5 mm² 2.0 mm² 2.5 mm² 4.0 mm² None 373. If machanical and fire safety are important factors, the wiring should be lead sheathed type conduit type C.T.S. type casing-caping type None 374. A stair case point is operated with: two one-way switches two two-way switches two intermediate switches none of these None 375. Outlets above 15 A rating should be connected through a: two-way switch D.P. switch T.P. switch D.P.S.T. switch None 376. What is the maximum permissible wattage of all the appliances on a 16A - fuse branch-circuit? 3.0 kW 3.9 kW ( 4.0 kW 4.6 kW None 377. In batten wiring, for the batten width of 19 mm what length of overlapping portion do you use for straight joint? 12 mm 25 mm 30 mm 40 mm. None 378. The rating factor which the normal current carrying capacity should be multiplied to get the permissible current in the cable for the circuits protected by close-excess current protection will be: 0.81 0.91 1.01 1.23 None 379. Which switch or switches can control the dressing table lamp ? Switch nos. 1 and 2 Switch nos. 2 and 3 Switch nos. 2 Switch no. 1 None 380. Which one of the following material is used to fix the screw on concrete wall and ceiling? Link clips Bushings Saddles Rowl plugs None 381. You have to install cables for a switch board using clips on batten. The distance between the accessories is 3.6 m. How many clips do you need for horizontal run of the cable? 20 27 37 70 None 382. In the metal conduit system of wiring where there is zig-zag wall projection the cables can be run using: standard solid bends standard inspection bends metal flexible conduit offset bends. None 383. For tapping supply from mains to different branches three types of layout for wiring system are used. As per IE regulation, one ring main circuit has to be there for every specified floor area or part there of. How much is this area? 100 sq. mts 120 sq. mts 150 sq. mts 160 sq. mts. None 384. The only wiring which has to be planned well before starting of a house construction work and executed alongwith the construction is: cleat wiring batten wiring conduit surface wiring conduit concealed wiring None 385. Corridor lighting for three lamps can be operated by: all lamps in 'ON' and 'OFF' position by two-way switches and two intermediate switches. independent light in 'ON' and 'OFF' position by two intermediate switches all lights in 'ON' and 'OFF' position by two intermediate switches both A and B None 386. According to NE code, the colour code inar for the neutral is: red blue black green None 387. To estimate the materials and cables, the head diagram which is very useful will be: laying diagram and wiring diagram. installation plan and circuit diagram circuit diagram and installation plan wiring diagram and circuit diagram. None 388. This diagram is not possible to be drawn for the entire wiring installation. But it is el noitsil drawn to get the approval of the customer to have overview. Layout diagram Installation plan Circuit diagram Wiring diagram None 389. Which type of looping method uses less cables in wiring? looping out from switch and ceiling rose looping out from switch looping out from 3 plate ceiling rose looping out with junction box None 390. While estimating in wiring for any enitua contingencies generally an additional amount of total cost is added 3 percent 7 percent 5 percent 10 percent None 391. The current capacities of the cables are rtis erspecified for certain ambient temperature enirlo in BIS regulations. The specified ambient aboine temperature is 20°C 30°C 40°C 50°C None 392. As compared to rewirable fuses, fuses have high rupturing capacity high speed of operation no ageing effect low rupturing effect None 393. The outer screwed contacts of Edison screw type lamp holder must always be connected to the neutral wire of the circuit phase wire of the circuit switch (half) wire of the circuit earth wire of the circuit None 394. As per standard practice the circuit of different phases should be kept at 3.5 metres 3.05 metres 2.55 metres 2.05 metres None 395. To reduce the length of cable in a wiring installation having same number of points and wired in loop in terminal system, one of the following wiring accessories is required. Identify the accessory Two way switch Intermediate switch Two plate ceiling rose Three plate ceiling rose None 396. While harnessing cables, it is recommended to use separate bundles for power and control wiring cables. The reason to separate the bundles is to avoid transfer of heat from power cables to control cables to avoid the mixing of both cables to make good appearance of wiring to avoid the wrong connection of both cables None 397. The under writer's knot is to be made on twin-twisted or twin-core flexible cable inside the accessories like pendent holders. What is the main reason? To avoid loose connection of the terminals To increase more mechanical strength To relieve the strain from the terminals of the accessory To prevent the excess wire outside the cap cover None 398. To determine the size of cable the following formula is given below as: bine Cross sectional area of the wire 2*K*L*1 /Voltage drop What does the letter 'K' represent in the above formula? K = Specific resistance of the conductor in ohm centimetre/m per cubic K= Insulation resistance of the cable onhiw in Mega ohm K= Resistance per sq mm per metre length of the conductor K = Cross sectional area of the conductor in sq mm None 399. Polarity test ensures safety to the user and also to the electrician. Verification of polarity in an installation is to ensure that the fuses are connected in the phase wire and the single pole switches are connected in the neutral wire the fuses are connected in the neutral wire and the single pole switches are connected to the phase wire the fuses and the single pole switches are connected in the phase wire the fuses and the single pole switches are connected in the neutral wire None 400. Which statement describes a characteristic feature of routine preventive maintenance? Maintenance schedule needs to be decided, based on the maintenance reports entered in the maintenance card Maintenance could be done either during the working of the machine or during short interval down periods. Maintenance is performed at irregular frequencies. Maintenance is only performed, if a machine has a fault or defect None 401. During continuity test in an installation, the megger indicated reading is O megohm 1 megohm 500 megohm Infinity megohm None 402. How many light points can be allowed in one circuit? 5 points 10 points 15 points 20 points None 403. How many power points can be allowed in one circuit? Four Three Two One None 404. The load on each sub-circuit shall be restricted to 800 W 750 W 700 W 650 W None 405. The rating factor of the circuit having coarse excess current protection is 1.63 1.23 0.81 0.61 None 406. Which device comes under the close excess current protection Rewirable fuse Cut out fuse Miniature Circuit Breaker ICDP main switch None 407. Normal current capacity of a certain cable is 16 amperes. If the circuit is protected by the close excess current protection, then the current capacity of the cable will be 12 amperes 13 amperes 16 amperes ( 20 amperes None 408. As per I.E. Rules, the leakage current in wiring installation should not exceed more than 1/50 -th part of full load current 1/ 500 -th part of full load current 1 / 5000 -th part of full load current 1 / 50000 -th part of full load current None 409. As per ISI code regulation, the load in each branch lighting circuit should not be more than 600 watts 800 watts 1000 watts None 410. The minimum thickness of non hinged boards should be 20 mm 25 mm 30 mm 40 mm None 411. The distance between clips in horizontal runs shall not exceed........ 20 cm 15 cm 10 cm 5 cm None 412. What is the minimum distance to be kept between link clips in the case of vertical runs? 20 cm 18 cm 15 cm 10 cm None 413. Which type of wiring is suitable for multi storey building Tree-system Ring main system Distribution board system Ring main and distribution board system None 414. Tree system of wiring is suitable for.......... single storied building multi storied building industrial wiring installation printing press None 415. Name the type of cables used for cleat wiring? Weather proof cables Vulcanized Indian Rubber Lead sheathed cables Tough Rubber Sheathed (TRS) None 416. Cleats shall be fixed at distance not PrtScr Insert + greater than ... apart at regular intervals. 65 cm 60 cm 55 cm 50 cm None 417. Which type of system is suitable for petroleum product factory? Batten wiring PVC conduit wiring PVC casing wiring. Metal conduit wiring None 418. Cables are drawn through the pipe and terminated. The system of wiring is called PVC casing capping wiring conduit wiring T.W. batten wiring T.W. casing capping wiring None 419. The radius of bends used in conduit wiring should not be less than 3 cm 5 cm 6 cm 7.5 cm None 420. The surface conduit wiring saddles should be fixed at intervals of not more than...... 0.5 m 0.75 m 1.0 m 1.5 m None 421. The thread on conduit pipes in all cases should have a length of range........... 10 to 20 mm 11 to 27 mm 12 to 25 mm 15 to 35 mm None 422. Which one of the following is the suitable pitch of hacksaw blade for cutting a heavy gauge conduit pipe? 1.8 mm 1.4 mm 1.0 mm 0.8 mm None 423. What is the wall thickness of 25 mm heavy gauge metal conduit pipe? 2.24 mm 2.00 mm 1.80 mm 1.60 mm None 424. Which one of the following is the most suitable fish wire to be used in conduit runs having more than a couple of bends? Copper wire Mild steel wire Stainless steel wire Steel curtain springs None 425. The best suitable fish wire to be used in conduit runs is........... Gl wire PVC wire VIR wire Aluminium wire None 426. What is the main disadvantages of the PVC casing and capping wiring system? Cost is more than other wiring system It is inflammable and risk of fire It is difficult to locate the fault It requires frequent maintenance None 427. The length of the PVC channel for wiring is available 2 metre 2.5 metre 3.0 metre 4.0 metre None 428. The size of PVC pipe for cold bending should not exceed 10 mm 15 mm 20 mm 25 mm None 429. The only wiring which can be taken through shortest route is the roof and required less right angle bends is. conduit surface wiring conduit concealed wiring casing and capping wiring batten wiring None 430. Laying of concealed wiring in roof starts, soon after completion of........ pouring concrete centering shuttering load bearing walls None 431. Concealed PVC conduit wiring requires Inspection elbows, bends and Tee's Solid elbows, bends and Tee's Conduit saddles Metal coupling with check nut None 432. Which one of the following is the normal wall thickness of PVC conduit pipes? 0.8 mm 1.0 mm ( 1.2 mm 1.6 mm None 433. In which one of the following wirings, three two way switches only are required to operate three lamps? Staircase wiring Corridor wiring Tunnel wiring Godown wiring None 434. In which type of wiring, two lamps are switched ON at a time? Tunnel wiring Hostel wiring Godown wiring Corridor wiring None 435. A staircase point can be operated...... with one one-way and one two-way switches with two one-way switches with two two-way switches with two intermediate switches None 436. Batten wiring is recommended for...... temporary house wiring permanent house wiring industrial wiring power wiring None 437. While fixing batten, the distance between. the fixing screws should not exceed 75 cm 7.5 cm 75 mm 7.5 mm None 438. T.R.S. cables on batten is suitable for high voltage extra high voltage ) low voltage medium voltage None 439. Raising main type distribution system is suitable for which type of multistoried buildings? Workshop buildings Substation buildings Residential flats Shopping complex buildings None 440. PVC channel wiring is suitable for go-down wiring industrial wiring out-door wiring indoor surface wiring None 441. Which one is the main disadvantages of PV.C. Channel surface wiring? ) Cost is more than other system Inflammable and risk of fire Frequent maintenance required More difficult to make wiring None 442. The number of wires of 4 sq. mm drawn in a 20 mm × 10 mm casing and capping 1 2 3 4 None 443. The number of wires of 6 sq. mm drawn in a 25 x 10 mm casing capping is 6 4 3 2 None 444. . which type of wiring system shall not be used in places exposed to sun and rain? Cleat wiring Batten wiring ( P.V.C. casing and capping Metal conduit wiring None 445. The only wiring which can be taken through shortest route in the roof and requires less right angle bends is casing and capping batten wiring conduit surface wiring conduit concealed wiring None 446. The main advantages of concealed wiring than the surface conduit wiring is that it requires less material fault location and rectification is easy installation cost is less inspection more easy None 447. Though four branch circuits are planned for a domestic installation, only one cable was connected from the four circuits to the neutral link. This will result in all lamps give more than normal brightness over loading of the phase cable saving of cable for the customer neutral conductor gets over heated None 448. In case the voltage drop exceeds 3%, then the technician has to choose. bigger size of wire double the size of wire half the size of wire next bigger size of wire None 449. The leakage current flowing in an installation is due to..... improper earthing high earth loop impedance ) insulation failure low earth resistance None 450. I.E. rule states the leakage current should not exceed...... 1 / 5000 th part of full load current 1/ 4000 th part of full load current 1 / 3000 th part of full load current 1 / 2000 th part of full load current None 451. As per IE rules, the leakage current in any wiring installation should not exceed more than.... 1/ 1000 th part of full load current 1/3000 th part of full load current 1/ 4000 th part of full load current 1/ 5000 th part of full load current None 452. The full form of BIS is Bureau of Indian Standards Bureau of Institute Standards Bureau of Indian Supply None 453. As per BIS the measured insulation resistance of any wiring installation should not be less than ) 100 ohm 1000 ohm 100 k.ohm 1000 k.ohm None 454. As per BIS, number of link clips per box are.... No. 100 90 80 70 None 455. Line clips are made out of Iron Nickel Zinc ) Tin None 456. . Link clips are made out of zinc nickel brass iron None 457. The thickness of link clips of 30 SWG is 0.28 mm 0.31 mm 0.30 mm 0.32 mm None 458. The process of removing a required length of wire end of insulation is known as.. skinning ) stripping straightening termination None 459. What is the name of the material used for harnessing cables while making wiring connection of motor? PV.C. saddles P.V.C. straps P.V.C. trays P.V.C. casting None 460. Which device is the example for coarse excess current protection? MCB HRC Cartridge fuse Rewirable fuse None 461. Normal current capacity of a certain cable is 16 amperes. If the circuit is protected by the course excess current protection, then the current capacity of the cable will be 12 A 13 A 16 A 20 A None 462. Types of cleats available are 4 3 2 1 None 463. Cleats are fixed at a regular distance of 75 cm 70 cm 60 cm 55 cm None 464. The sub circuits are divided into. 5 4 3 2 None 465. The load on each sub circuit shall be restricted to.... 800 watts 1500 watts 1200 watts ( 1000 watts None 466. The cross sectional area of copper conductor for power wiring shall be not less than.. 0.5 mm² 1.15 mm² 1.15 mm² 2.5 mm² None 467. The minimum size of aluminium conductor used in a power circuit is 1 sq mm 2.5 sq mm 4 sq mm 1.5 sq mm. None 468. The clearance between the conductors of opposite polarity or phase and between the conductors shall be at least.. 5.0 cm 3.5 cm 2.5 cm 2.0 cm None 469. If the working voltage of an installation is 220 volts, then insulation tester rated voltage is.. ) 2000 V 1500 V 500 v 1000 V None 470. As per NEC, the phase apparatus (output) A.C. system in Aplha-numeric natation is represented as L, LL, N R, Y, B. N A, B, C, N U, V, W, N None 471. As per IE rules, the voltage at the point of commencement of supply in the case of high or extra high voltage, shall not vary more than.... 12.5 percentage 10.0 percentage 5.0 percentage ) 2.5 percentage None 472. The types of conduit used for wiring is 2 3 4 5 None 473. The metal conduits can be protected against corrosion by. galvanizing applying varnish applying oil wrapping adhesive tape None 474. The non metallic conduit pipe used in wiring, should have a minimum size in diameter is... 15 mm 18 mm 20 mm 25 mm None 475. The wall thickness of heavy gauge 20 mm size of conduit is.. 1.0 mm 1.2 mm 1.8 mm ) 2.0 mm None 476. The size of P.V.C. conduit pipe in diameter to be preferred for domestic wiring is... 21 mm ( 19 mm 18 mm 17 mm None 477. Domest While bending the conduit pipe, the minimum bending radius of conduit shall be 9.0 cm. 7.5 cm 6.0 cm 5.0 cm None 478. While fixing the conduit pipes by saddles, the distance must be at either end of the fitting is.... 30 cm 25 cm ) 20 cm 15 cm None 479. The threads on the conduit pipe in allcases shall be between. 10 mm to 27 mm long 12 mm to 28 mm long 13 mm to 29 mm long 14 mm to 30 mm long None 480. The conduit elbows are used at ) tapping the connection sharp ends straight runs away from walls None 481. The minimum depth of junction boxes used in roof slabs shall be 75 mm 70 mm 65 mm 60 mm None 482. Teak wood battens are commercially available with length varying from...... 1 m to 1.5 m 1 to 2.0 m 1 m to 2.5 mm 1 m to 3.0 m None 483. The size of T.W. batten commercially available with a thickness is........ 12 mm x 12 mm 12 mm x 13 mm 12 mm x 14 mm 12 mm x 15 mm None 484. Minimum thickness of TW batten shall not be less than 8 mm 10 mm 12 mm 15 mm None 485. The size of commercially available T.W. round block single is 72 mm x 25 mm 73 mm x 25 mm 74 mm x 25 mm 75 mm x 25 mm None 486. T.W. board for fixing main switches sizes available is.... 80 mm x 80 mm 85 mm x 85 mm 90 mm x 90 mm 100 mm x 100 mm ( None 487. The size of commercially available T.W. round block single is ( 75 mm x 37 mm 75 mm 38 mm 75 mm x 39 mm 75 mm x 40 mm None 488. . T.W. board for fixing mains are available in 110 mm x 80 mm 120 mm x 80 mm 130 mm x 80 mm 150 mm x 80 mm None 489. Which among these is a method of wiring? Joint Box Tee system Loop in system All of these None 490. Which of the following is not a disadvantage of the loop in system of wiring? More material used No junction boxes required More expensive Domes None 491. Two pin sockets should not be used in domestic wiring unless the appliance to Double earthed Double insulated Controlled by ELCB Controlled by MCB None 492. The wiring system generally employed in public building (offices) Cleat wiring Cassing-Capping wiring C.T.S. wiring Conduit wiring None 493. What type of wiring will you suggest in a cold storage? Batten wiring PVC/CTS Conduit wiring PVC/lead covered wiring Cleat wiring None 494. Red colour wire is generally known for Earth Neutral Phase Insulated wire None 495. Before working on any electric conductor, it should be discharged and also to prevent the same from being charged by mistake, the 1.E.R. is...... L.E.R. 1956 Rule No. 38 ) LE.R. 1956 Rule No. 36 LE.R. 1956 Rule No. 35 I.E.R. 1956 Rule No. 34 None 496. One light fan, sub circuit of domestic wiring allows maximum wattage of - 500 w 2000 W 800 W ) 3000 W None 497. . A factory requires power points for its loads, 2 nos.-2.5 kW, 2 nos. -1.5 kW. 10 nos. -0.9 kW. The optimal no. of power sub-circuit will be 5 6 7 8 None 498. The insulation resistance of an installation is more than.... 1 ohm 1 mega ohm ) 2 kilo ohms 5 mega ohms None 499. The maximum load can be taken from a 5 ampere fuse distribution board is 1000 watts ( 800 watts 3000 watts 5000 watts None 500. Each appliance in a sub circuit is operated by a separate fuse in Looping system Tree system Ring system Distribution system None 501. In cleat wiring, typical cleats used for holding the cables are available in .... Single piece Two parts Four parts Three parts None 502. Type of wiring system in which wires. sheathed in tough rubber, clipped on wooden battens with brass clips is..... Cleat wiring C.T.S. Casing cappling All of these None 503. The wiring of electrical motors in the industries is carried out according to requirement of I.E. Rule No. .. 40, 41 50, 51 55, 57 71, 72 None 504. According to I.E. rule, maximum allowable power and number of power points in a power sub circuitt are 3000 W, 2 2000 W, 3 2000 W, 1 3000 W, 3 None 505. In order to design a domestic connection with four ceiling fans, eight lamps and six power points, the minimum number of light fan sub circuit and power sub circuit are 4,2 2,3 2.6 4.3 None 506. What is the maximum load that can be connected in a circuit connecting lighting load only 500 W 750 w 800 W 1000 W None 507. What is maximum number of lighting points that can be connected in a circuit? 5 10 8 12 None 508. Which of the following is not a feature of a good wiring design? Equal voltage distribution Varying load current in each circuit Easy repair and maintenance Safety to the consumer None 509. Following is/are true about neutral wiring Neutral grounding eliminates that need to earth point in three/five point sockets An open neutral path indicates no current flow through the respective current/sub circuit An open neutral path indicates balanced current through the three phase load All of these None 510. Megger is an instrument meant for measuring very low resistance insulation resistance inductance of a coll 'Q' of a coll None 511. The operation of a Megger is based on moving-iron meter electrodynamic meter electrostatic meter moving coil meter None 512. A megger is exclusively designed for measuring: very high resistance very low resistance ground faults in power lines. None 513. What instrument is used to measure the insulation resistance of an installation? Megger Earth tester Multimeter Ohm meter None 514. For measurement of insulation resistance, the best instrument is megger as it measures accurately in the range of milli ohms kilo ohms mega ohms giga ohms mega ohms None 515. The instrument used to measure the insulation resistance of an electric circuit relative to earth and one another is Tangent galvanometer Megger Potential Transformer Current Transformer None 516. When megger is not in use, pointer position..... ) comes back to zero Remains anywhere on the scale Goes to infinity None of these None 517. In open circuit, megger reading is Zero kilo ohms infinity ohm None 518. Feedback used in a RC oscillator is of negative type positive type any type, positive or negative none of the stated above None 519. In RC oscillator the phase of the feedback voltage is shifted to by employing a RC phase shifting network- 0° 60 90° 180° None 520. An amplifier can work as an oscillator when its loop gain becomes infinity 0 -1 +1 None 521. Weinbridge Oscillator uses- positive feedback both positive and negative feedback negative feedback none of the stated abvoe None 522. An oscillator which generates sine wave oscillations is called- damped wave oscillator relaxation oscillator feedback oscillator harmonic oscillator None 523. . An oscillator which generates non sinusoidal waves is called harmonic ocillator feedback oscillator relaxation oscillator none of the above None 524. The frequency generated by an oscillator can be measured by means of- a voltmeter a frequency meter ) either CRO or an electronic frequency counter an AVO meter None 525. The amplitude of damped waves decreases with time increases with time is zero is constant None 526. A parallel-fed Hartley oscillator is series-fed circuit because of preferred lower cost higher frequency stability lower power consumption circuit simplicity None 527. A Colpitt's Oscillator employs inductive feedback capacitive feedback negative feedback stray capacitance feedback None 528. Crystal oscillators are used in transmitters be of their- frequency stability property low cost rigidness simplicity None 529. A Colpitt's oscillator generates square waves sine waves saw-tooth waves damped waves None 530. . An oscillator circuit which is meant for converting sine wave signal into square wave signal is called a Schmmitt trigger blocking oscillator multivibrator Weinbridge oscillator None 531. In a RC phase shift oscillator, the frequency generated depends on- Ve applied transistor used in the circuit time constant of RC network all the components mentioned above None 532. Square wave signals play important role in - amplifiers rectifiers oscillators digital equipments None 533. A sinusoidal oscillator is an amplifier with feedback. no positive negative None 534. To initiate oscillation, the loop gain of the oscillator must be unity less than equal to greater than equal to or less than None 535. 1 mega hertz oscillator produces a wave whose length 3 metres 3 cm 300 metres 300 cm None 536. A Colpitts oscillator uses a tapped inductor a tapped capacitor no tapped inductor or capacitor both tapped inductor and capacitor None 537. Crystal oscillator is used because it gives higher output voltage it has high efficiency the frequency of oscillations remains substantially constant. It requires very low D.C. supply voltage None 538. An audio oscillator uses positive feedback negative feedback ) both positive and negative feedback non of these None 539. Wein bridge oscillator is basically a pulse generator sine wave generator square wave generator triangular wave generator None 540. In a transistor Hartley oscillator, inductive feedback is used. ) untapped coil is used entire coil is in the output circuit none of the above None 541. To generate a one mega hertz signal, the most suitable oscillator is Colpitt's oscillator phase shift oscillator ) Wein brdige oscillator none of these None 542. In an RC phase shift oscillator, the minimum number of R.C networks to be connected in cascade will be one two three four None 543. The most stable sine wave oscillator is Colpitts Armstrong Phase shift crystal None 544. If RF signal is 600 kHz and local oscillator frequency is 1000 kHz, then the output of the mixer will be 400 kHz 600 kHz 1000 kHz 1600 kHz None 545. A bistable multivibrator has no stable state. has two stable states. has one energy storage element switches between its two states automatically None 546. A bistable multivibrator is a triggered oscillator. crystal oscillator. free running oscillator sawtooth wave generator None 547. Schmitt trigger is basically an astable multivibrator a bistable multivibrator. a monostable multivibrator an oscillator. None 548. Trigger pulses are essential for the operation of a bistable multivibrator because there are no RC timing circuits the circuit cannot switch between its two states automatically. transistor operation is controlled by the triggering pulses. all of these None 549. The frequency of oscillation in case of an astable multivibrator depends mainly on the value of transistor B RC values of the circuit value of V power supply Collector resistors. None 550. In a multivibrator feedback between two stages is 100% feedback employed is positive when one transistor is on, the other is off all of the above. None 551. For generating a 1 kHz signal, the most suitable circuit Hartley oscillator Colpitts oscillator un tuned collector oscillator Wein bridge oscillator None 552. On removing the cores of a transformer, the production of magnetic flux is reduced is increased remains the same none of these. None 553. The no. of magnetic paths in a berry type transformer: is one are two are three are numerous. None 554. In a transformer, the linkage of magnetic flux takes place from primary to secondary secondary to primary primary to secondary and from secondary to primary none of these None 555. Since, the cores of a transformer are made of silicon- steel, therefore: copper-loss remains low eddy-current-loss remains low hysteresis-loss remains low both copper and eddy-current losses remain low None 556. The efficiency of a transformer stands high because it works on the principle of mutual induction it is a static instrument its windings remain immersed in the mineral oil there is no loss of electric power in it. None 557. For equal capacity, a shell type transformer as compared to a core type transformer will have low copper-loss low iron-loss low copper and iron losses high copper and iron losses. None 558. If the supply frequency of a transformer is reduced then its iron-loss will be low high the same very high None 559. If the transformers have different voltage ratios and their parallel operation is desired then: they will not work on load they will not work at all ( they will work at different power factors they will work at an average voltage. None 560. the capacity of a star-connected transformer as compared to a delta-connected transformer will be 1/3 times 3 times 1/2 times equal. None 561. In the breather of a transformer, silica-jelly is used to stop the rain water to reach upto the insulating oil: dry air moisture steam. None 562. The principle of working of a transformer is: static induction self induction mutual induction dynamic induction None 563. A transformer operates always at unity power factor at its own power factor at a power factor below a particular value at a power factor depending on the power factor of the load None 564. A transformer is used for changing the value of : voltage frequency ( power power factor. None 565. The reactance of a transformer is determined by its common core flux leakage flux size of the core permeability of the core material None 566. The efficiency of a transformer is normally in the range of 50% to 70% 60% to 75% 80% to 90% ) 90% to 98% None 567. Eddy-current loss in a transformer can be reduced by: increasing the thickness of the laminations decreasing the thickness of the laminations winding the coils with a higher gauge wire decreasing the air-gap in the magnetic circuit. None 568. The main property of a transformer is this that it without changing its power without changing its frequency without changing its shape without changing its power, frequency and shape. None 569. Transformers are rated in: kW kV kWh kVA None 570. What type of core is used in a transformer designed to work at high frequencies (MHz range)? Aluminium core Iron core Air core Open type iron core. None 571. . If the secondary turns of a transformer are doubled and at the same time the primary voltage is reduced be halved to half then the secondary voltage will: be doubled not change be four times high None 572. The no-load current of a transformer in terms of full- load current is usually 1% to 2% 5% to 12% 2% to 5% 12% to 20% None 573. Which is the common method of a cooling a power transformer used in distribution work? Air cooling Air-blast cooling Oil cooling Water cooling None 574. The transformer oil used in transformers provide cooling and lubrication insulation and lubrication insulation and cooling insulation, cooling and lubrication None 575. What is the typical use of an auto transformer? To work as a control transformer To work as a variable transformer ) To work as a distribution transformer To work as an isolating transformer. None 576. As compared to an amplifier, a transformer cannot increase output power increase output voltage increase output current none of these None 577. A conservator used in a transformer consists of: an air-tight metallic drum fixed at the top of the oil-tank an air-tight metallic drum fixed at the bottom of the oil-tank overload protection device none of these. None 578. In a power transformer, the winding nearer to the iron core is a high voltage winding is a low voltage winding may be low or high voltage winding the two types of windings are placed in a sandwich manner. None 579. A good transformer oil should be free from alkali sulpher moisture all the above. None 580. the load depending upon their rating in KVA efficiency leakage reactance per unit impedance None 581. In an ideal transformer, the no-load primary current is in phase with V Lags behind V, by 90° Leads V, by 90° ) lags V, by an angle lying between 0° and 90° None 582. Which of the following reduces high voltage and current to safe values of measurement ? Megaohmmeter Auto transformer Variable transformer Instrument transformer. None 583. When a transformer is operating on no load, the primary applied voltage is approximately balanced by Secondary induced e.m.f. Primary induced e.m.f. terminal voltage across the secondary voltage drop across resistance and reactance None 584. Which one of the following methods will be preferred for a transformer cooling, above 200 kVA ? Insulating oil Air blast Oil natural, Air forced Oil forced, Water forced. None 585. Scott connections are used to transform: single-phase supply into three-phase supply single-phase supply into two-phase supply three-phase supply into two-phase supply star-connected primary into delta-connected secondary. None 586. None 1 out of 59 Name Email Time's upTime is Up!
