1. If there is a regular moment of …… within a material, we say that an electric current is flowing 1) protons 2) electrons 3) atoms 4) ions 2. The rate of flow of an electric current is measured in 1) coulombs 2) amperes 3) ohms 4) mhos 3. One coulomb represents a quantity of 1) 0.624X1018 electrons 2) 624X1012 electrons 3) 6.24X1019 electrons 4) 6.24X1018 electrons 4. If three coulombs of electricity flow through a conductor in three seconds the current is 1) one ampere 2) one half ampere 3) six ampere 4) one third ampere 5. The presence of an electric current is made known by 1) flashing 2) effects produced 3) cracking 4) electric shock
6. When an electric current flows through a conducting liquid, a …… change is produced 1) chemical 2) magnetic 3) mechanical 7. In mathematical form ohm’s law can be written as 1) V I=R 2) V =IR 3) V=I/R 4) VR=I 8. Ohm’s law does not apply to 1) conductors 2) conductors when there temperature 3) semi-conductor 4) a.c. circuits
is
change
in
9. If a piece of metal wire is stretched, its resistance will increase 1) True 2) False 10. The material used for fuse must have 1) low melting point and low specific resistance 2) low melting point and high specific resistance 3) high melting point and low specific resistance 11. When an electron is removed from an atom it becomes 1) a positive ion 2) an anode 3) a cathode 4) a negative ion 12. Absolute permitivity of vacuum is taken as 1) 8.854X10-6 farad/m 2) 8.854X10-12 farad/m 3) 8.854X10-9 farad/m 13. Relative permittivity of vacuum is 1) zero 2) 8.854X10-6 3) unity 14. Dielectric strength of a material depends on
1) moisture content 2) thickness 3) temperature 4) all the above 15. What will happen to an insulating medium of voltage more than the breakdown voltage is applied or it 1) it will get punctured 2) it will become magnetic 3) it will melt 4) its molecular structure will change 16. Capacitors are said to 1) block a.c. and pass d.c. 2) block d.c. and pass a.c. 3) pass a.c. and d.c. 4) block a.c. and d.c. 17. To increase the capacitance of a capacitor, the plates must be placed 1) further apart 2) closer together 3) in series 4) made smaller 18. In a radio a gang condenser is a type of 1) air capacitor 2) paper capacitor 3) ceramic capacitor 4) electrolytic capacitor 19. In a capacitor the electric charge is stored in 1) metal plates 2) dielectric 3) dielectric as well as metal plates
20. 4 condensers of 4 µ F each are connected in parallel. Their equivalent capacitance will be 1) 16 µ F 2) 64 µ F 3) 4 µ F 4) 1 µ F
21) When two capacitors C1 and C2 are connected in series, the effective capacitance is C1+C2 1) True 2) False 21. An uncharged capacitor is connected across a charged one. There will flow an impulsive current through the circuit. 1) True 2) False 22. Current and voltage in an a.c. resistive circuit are 1) 900 out of phase 2) in phase 3) 900 out of phase current leading voltage 4) 1800 out of phase. 23. Current and voltage in a.c. inductive circuit are 1) 900 out of phase 2) in phase 3) 900 out of phase voltage leading current 4) 900 out of phase voltage lagging current 24. Alternating current frequency is the number of 1) alternation per minute 2) cycles per minute 3) alternation per second 4) cycles per secon4)
25. The greatest value attained during one half of the cycle is called the 1) peak value 2) average value 3) r.m.s value 4) effective value 26. The root mean square (r.m.s) value of a.c. is the same as 1) instantaneous value 2) effective value 3) average value 4) maximum value 27. The r.m.s value of a sine wave is equal to 1) 0.637 max. value 2) 0.707 max. value 3) 0.506 max. value 4) 1.414 max. value 28. Form factor is defined as 1) r.m.s value/peak value 2) max. value/r.m.s value 3) r.m.s value/average value 4) effective value/r.m.s value 29. The value of form factor for a pure sine wave is 1) 1.414 2) 0.707 3) 0.637 4) 1.11 30. The value of peak factor for a pure sine wave is 1) 1.414 2) 0.707 3) 0.637 4)1.11 31. At resonance, the phase angle is equal to 1) 1800 2) 900 3) 450 4) 00 32. The condition of resonance is 1) XL >XC 2) XC < XL 3) XL=XC 33. According to KCL as applied to a junction in a network of conductors 1) total sum of currents meeting at the junction is zero 2) no current can leave the junction without some current entering it. 3) Net current flow at the junction is positive. 4) Algebraic sum of the currents meeting at the junction is zero 34. Kirchhoff’s current law is applicable to only. 1) closed loops in a network 2) electronic circuits 3) junctions in a network 4) electric circuits 35. Kirchhoff’s voltage law is concerned with a. I R drops 2) battery e.m.f.s 3) junction voltage 4) both a and b 36.
According to KVL, the algebraic sum of all I R drops and e.m.f.s in any closed loop of a network is always 1) zero 2) positive 3) negative 4) determined by battery e.m.fs 37. The algebraic sign of an IR drop is primarily dependent upon 1) amount of current flowing through it 2) value of R 3) direction of current flow
4) battery connection 38. The unit of absolute permittivity of a medium is 1) joule/coulomb 2) newton-meter 3) farad/meter 4) farad/coulomb 39. The unit of electric intensity is 1) joule/colomb 2) Newton / coulomb 3) volt/metre 4) both b and c 40. Inside a conducting sphere,____ remains constant 1) electric flux 2) electric intensity 3) charge 4) potential 41. A capacitor consists of two 1) insulators separated by a dielectric 2) conductors separated by an insulator 3) ceramic plates and one mica disc 4) silver-coated insulators 42. A capacitor that stores a charge of 0.5 C at 10 volts has a capacitance of --------- farad 1) 5 2) 20 3) 10 4) 0.05 43. If e1=A sin wt and e2=B sin (wt-θ ), then 1) e1 lags e2 by θ 2) e2 lags e1 by θ 3) e2 leads e1 by θ 4) e1 leads e2 by θ 44. The unit of conductivity is : 1) ohms 2) Ω -m 3) Siemens candela
4)
45. In case of short circuit : 1) voltage is ∞, current is ∞ 2) voltage is 0, current is 0 3) voltage is 0, current is ∞ 4) voltage is ∞, current is 0 46. Capacitance of spherical capacitor is : 1) 4π ε 0ε rd 2) ¼π ε 0d 3) 4π ε 0ε r(b-a)/ab 4) 4π ε 0ε r (ab)/(b-a) 47. The energy stored in a capacitor is given by : 1) ½ C2V 2) ½ QV 3) C2/2Q 4) None of the above. 48. Capacitance of a variable capacitor is given by : 1) n. ε 0ε rA/d 2) ε 0ε rd/A(n-1) 3) (n-1) ε 0ε rA/d 4) 4ε 0ε r(b-a)/(ab) 49. The % tolerance for gold is 1) 5% 2) 2% 3) 10% 4) 20% 50. In colour coding of resistance. If the colours are brown, black, red the value of resistance is : 1) 100Ω 2) 1000 kΩ 3) 100 kΩ 4) 1 kΩ
51) The direction of magnitude field set up in a current carrying conductor can be found out by 1) flemings left hand rule 2) cork screw rule 3) flemings right hand rule 4) thumb rule 52) The unit of mmf is – 1) volt c) coulomb
2) amp-turns 4) None
53) The low that induced emf and current always oppose th cause producing it is discovered by 1) Fleming 2) faraday 3) Lenz 4) Maxwell
64) During discharge of a battery voltage of cell – 1) decreases 2) increases 3) remains constant 4) none 65. The condition in ohm’s law is that 1) the temperature should remain constant 2) ratio V/I should be constant 3) the temperature should vary 4) current should be proportional to voltage
54) What are the minimum requirements to cause the flow of current 1)a voltage source and a conductor 2) a voltage source conductor and insulator 3) a voltage source, switch and resistor 4) a voltage source ammeter and a conductor
66. Kirchoff’s law states that in a closed loop of a circuit 1) The total currents, algebraically summed is zero 2) the algebraic sum of the potential differences is zero 3) the voltage across the components is zero 4) none
55. The co-efficient of self inductance of a coil is defined as – 1) ∅/NI 2) NI/∅ 3) N∅/I 4)∅ I/N
67. Angle between voltage and current is called – 1) peak factor 2) power factor 3) form factor 4) none
56. Tesla is a unit of – 1) flux 2) field strength 3) flux density 4) none
68. The ratio of maximum value to r.m.s. value is called 1) peak factor 2) ferm factor 3) utilisation factor 4) maintenance factor
57. The direction of magnetic lines of forces – 1) from one end of magnet to another 2) from north, pole to south pole 3) from south to north pole 4) none 58. Battery is a device that – 1) generate emf by chemical action 2) converts mechanical energy into electrical energy 3) converts heat energy into electrical energy 4) None 59. In a primary battery – 1) chemical action is reversible 2) chemical action is irreversible 3) no chemical action takes place 4) chemical action takes place 60. Active elements in a lead acid battery – 1) nickel hydrate and iron oxide 2) lead peroxide and sponge lead 3) manganese dioxide and carbon 4) sponge lead 61) Electrolyte used in lead acid battery is 1) sulphuric acid 2) caustic potash 3) nitric acid 4) none 62) When the temperature increased, specific gravity of electrolyte 1) increases 2) decreases 3) remains same 4) none 63) The capacity of a battery is expressed in 1) ampere-hour 2) ampere volt 3) percentage 4) volts
69. The reactance of an inductance L connected to an a.c. source frequency f is 1) fl 2)π f2l 3) 2 π fl 4) ½π fl 70. If a capacitor is connected to an a.c. source the current – the source voltage by 1) lags 900 2) lags 450 0 3) leads 90 4) none 71. If a circuit the voltage. Is doubled and the resistance is cut in half at the same time the current will be 1) doubled 2) a quarter 3) a half 4) four times as high 72. What is meant by permeability – 1) strength of a permanent magnet 2) strength of a electromagnet 3) repulsion of two similar poles 4) conductivity of a material for the magnetic flux 73. The parallel conductor are carrying current in the same direction. Which of the following statement is correct 1) there is a repelling force 2) the force increases when current decreases 3) there is an attracting force between the conductors 4) the force increases when the distance between conductor increases 74. The direction of the induced current depends upon 1) length of conductor 2) speed of movement of conductor
3) strength of magnetic field 4) direction of magnetic field 75. Which is the symbol and unit for inductance 1) Rm weber (wb) 2) XL henry (h) 3) L gauss (G) 4) henry (H) 76. In a stationery conductor an emf can be induced by 1) a changing magnetic field 2) positive and negative charges 3) a steady magnetic field 4) none 77. The induced emf is max. if the conductor cuts the magnetic field at 1) 00 2) 450 3) 900 4) none 78. The power factor of a purely resistive circuit is – 1) zero 2) lagging 3) leading 4) unity 79. Power factor is the rates of 1) Z/R 2) R/Z 3) XL/Z 4) Xc/z
80. A R-L-C series ckt. Has a resistance of 6Ω , inductive reactance of 8 Ω and capacitive reactance of 16Ω . The impedance will be 1) 10Ω 2) 16Ω 3) 8Ω 4) 6Ω 81. The max. value of the cycle is known, the r.m.s. value can be found at – 1) 0.707 X instantaneous value 2) 0.606 X instantaneous value 3) 0.707 X emax value 4) 0.707 X Eav value 82. a.c. can be easily lowered and raised by – 1) converter 2) motor generator set 3) transformer 4) rectifier 83. The max. & min. valued of power factor is – 1) 1 and 0 2) +1 and –1 3) +1 and –5 4)+ 5 and –5 84. Kirchoff’s laws are applicable to 1) dc circuit only 2) both dc and ac circuits 3) a.c. circuit only 4) none 85. An alternating current or voltage is that which 1) changes in direction only 2) changes in magnitude only 3) changes in both magnitude and direction 4) has a random movement of electron 86. In an a.c. circuit containing inductance only – 1) current lead voltage by 90 0 2) current lags behind utg by 90 0 3) current and voltage are in phase 4) voltage leads current by help a cycle 87. Relation between frequency and time period –
1) f =T
2) f = 1-T
3) f = T-1 4) f = 1/T
88. What is meant by frequency of an alternating voltage 1) No of full periods in one second 2) no. of direction reversals in one second 3) no. of direction reversals in one minute 4) no. of half periods in one second 89. What is meant by “current and voltage are in phase“ 1) voltage and current are of the same magnitude 2) voltage and current have the same frequency 3) the voltage leads the current in time 4) voltage and current reach their max. and zero value at the same time 90. When current passes through a conductor, the resultant effect is 1) a magnetic field is produced 2) magnetic as well as heating effect 3) only heating effect 4) only chemical effect 91. The nature of current flowing in armature of etc machine is – 1) dc 2) alternating 3) pulsating 92. Brushes are provided in a dc machine for 1) providing a path for the flow of current 2) preventing sparking 3) reducing losses 4) none 93. The armature of a dc machine is laminated to reduce 1) eddy current loss 2) hysterisis loss 3) copper loss 4) friction loss 94. The emf generated of a given dc generator depends upon 1) flux only 2) speed only 3) flux and speed 4) terminal voltage 95. If the speed of prime mover of a dc generator is increased the generated emf 1) increases 2) decreases 3) remains constant 96. Commutator in a ac generator is used for – 1) converting dc to ac 2) changing ac to dc 3) reducing friction 4) collecting the current from armature 97. Commutator of dc motor serves the purpose of 1) changing ac into dc 2) converting dc into ac 3) avoiding arc at brushes 4) reducing friction 98. On loading the speed of a dc shunt motor 1) increases 2) remains constant 3) slightly decreases 4) decreases sharply 99. A dc series motor is started on no load its speed is 1) zero 2) normal 3) infinite
100.Which of the following motors gives a high starting torque 1) series motor 2) shunt motor 3) compound motor 101.In dc machine at max. efficiency 1) Iron losses = armature copper losses 2) variable losses = constant losses 3) iron losses + mechanical losses + armature copper loss + shunt field loss 4) none 102.Why is the air gap between the yoke and armature of an electric motor kept smaller – 1) to achieve a stronger magnetic field 2) to avoid overheating of machine 3) both a & b 4) none 103.The function of starter in a dc machine 1) to avoid excessive current at starting 2) to control speed 3) to avoid armature reaction 4) none 104.An emf is induced in the windings of an armature of a generator when the armature rotates in 1) alternating magnetic flux2) magnetic field 3) electrostatic flux 4) electromagnetic flux 105.If the speed of dc generator is increased the generated emf 1) increases 2) decreases 3) remains constant 4) decreases then increases 106.If speed of dc shunt motor increases, the back emf 1) increases 4) decreases 3) remains constant 4) none 107.The efficiency of any electrical machine/ apparatus will be high if 1) its losses are minimum 2) its losses are more 3) voltage applied is constant 4) current drawn is min. 108.The direction of rotation of a dc shunt motor is reversed by – 1) reversing armature connection 2) interchanging the armature and field connection 3) adding resistance to field circuit 4) both a and c 109.Which of the following dc motor has the least drop in speed between no load to nominal load – 1) shunt motor 2) series motor 3) compound motor 110.Which of the following motor is used to drive the constant speed line shafting lathes, blowers and fans 1) dc shunt motor
2) dc series motor 3) commutative compound motor 4) none 111. DC series motor are best suited for traction because 1) torque is proportional to the square of armature current and speed is inversely proportional to torque 2) torque is proportional to the square of armature current and speed is proportional to torque 3) torque and speed are proportional to square of armature current 4) none 112. An ideal dc generator has a regulation of – 1) zero 2) 50% 3) 75 % 4) 100% 113. A dc generator can be termed as – 1) rotating amplifier 2) prime mover 3) power pump 4) none 114. The function of equalising connections in a lap wound dc generator is – 1) To neutralise the armature reaction effect 2) to avoid unequal distribution of currents at brushes 3) to avoid shot circuit current 4) none 116. Transformer is used to change the values of 1) voltage 2) frequency 3) power 4) power factor 117. The path of magnetic flux in a transformer has1) high reluctance 2) low resistance 3) high conductivity 4) low reluctance 118. Transformer is a 1) rotating device 2) static device 3) magnetic device 119.Transformer works on 1) ac 2) dc 3) ac and dc both 4) pulsating dc 120.Transformer works on the principle of – 1) self induction 2) mutual induction 3) faraday’s law and electromagnetic induction 4) self and mutual induction both 121.Rating of transformer is given in 1) KVA 2) KVAR 3) KW 4) Watts 122.If a higher voltage is given to primary and lower voltage is taken from secondary of transformer is it called 1) step up 2) step down 3) instrument transformer 4) stabiliser 123.The transformation ratio of a transformer is – 1) I 2/ I 1 2) N1 / N 2 3) N 2 / N 1 4) All
124.The emf induced in secondary winding depends upon 1) no. of turns 2) flux 3) supply frequency 4) all 125.When the secondary of the transformer is loaded, the flux in the transformer will – 1) remain constant 2) directly proportional to secondary current 3) directly proportional to the current drawn by primary 4) none 126.When secondary of the transformer is loaded, the current in primary side will – 1) not be effected 2) increase 3) decrease 4) be the sum of no load current and excessive current drawn due to secondary winding 127.Electric power is transferred from one coil to the other coil in a transformer – 1) electrically 2) electro-magnetically 3) magnetically 4) physically 128.A transformer operates 1) always at unity power factor 2) has its own power factor 3) at a power factor below a particular value 4) at power factor depending on the power factor of load 129.The laminations are made from 1) silicon sheet steel 2) nickel alloy steel stamping 3) low carbon steel 4) chrome sheet steels 130.Which of the following is a correct statement about eddy current 1) Eddy current improves the efficiency of a motor 2) 2) eddy current heat up the metal part 3) eddy current used for arc welding 4) none 131.The steel for construction of transformer core is made to have 1) high permeability and loss hysterisis loss 2) low permeability and high hysterisis loss 3) low permeability and low hysterisis loss 4) high permeability and high hysterisis loss 132.As compare to an amplifier, transformer can not 1) increase the output voltage 2) increase the o/p current 3) increase output power 4) none 133. The voltage transformation ratio is 1) E 1 / E 2 2) N 1 / N 2 3) E 2 / E 1 4) none 134. In a transformer a sinusoidal emf – 1) lags the flux inducing it by 180 0 2) lags the flux inducing it by 90 0
3) leads the flux inducing it by 180 0 4) leads the flux inducing it by 90 0 135. The no load current of a transformer in terms of full load current is usually – 1) 1 to 3 % 2) 3 to 15 % 3) 9 to 12 % 4) 12 to 20 % 136. If in a transformer the secondary turns are doubled and at the same time the primary voltage is reduced by half, then the secondary voltage will – 1) be halved 2) be four times as high 3) not change 4) be reduced to a quarter 137. Which of the statement given below is correct for the auto transformer 1) it has to separate windings connected in series externally 2) it has only one winding 3) it can only step down the voltage most 4) suitable for power transformation 138. In any transformer the voltage per turn in primary and secondary remains – 1) always same 2) always in ratio of K 3) always different 4) sometimes same 139. In a single phase transformer the primary and secondary induced voltages are 1) 180 0 out of phase 2) 90 0 out of phase 3) in phase 4) none 140.An ideal transformer is one which 1) has a common core for its primary and secondary windings 2) has no losses and magnetic leakage 3) has core of stainless steel and windings of pure copper metal 4) has interleaved primary and secondary windings 141.In an ideal transformer the no load primary current is 1) lags behind v1 by 90 0 2) is in phase with v1 3) leads v1 by 90 0 4) lags v 1 by an angle lying b / w 0 0 and 90 0 142.By definition a step down transformer is one in which 1) secondary current is more than primary current 2) secondary turns are less than primary turns 3) secondary winding consists of thinner copper wire 4) secondary power is less than primary power 143.The r.m.s value of a.c. is the same as : (1). Instantaneous value (2) effective value (3) average value (4) maximum value 144. The r.m.s value of a sine wave equal to : (1). 0.637 max. value (2) 0.707 max. value (3) 0.506 max. value (4) 1)414 max. value
145.Form factor is defined as : (1). r.m.s value /peak value (2) max. value/r.m.s value (3) r.m.s value/average value (4) effective value/r.m.s value 146.A unique feature of wire wound resister is its 1) low power rating 2) very high stability 3) low cost 4) smaller size 147. The working voltage of a capacitor in an ac circuit should be 1) equal to average voltage 2) at least 20% smaller than the highest applied voltage 3) at least 50% greater than the highest applied voltage 4) at least 50% less than the r.m.s valve of applied voltage 148. Kirchhoff’s laws can be used for 1) ac only 2) dc only 3) ac & c both 4) for rectified ac & pulsating dc 149. In practice, earth is chosen as a place of zero electric potential because it 1) is non conducting 2) is easily available 3) has almost constant potential 4) keeps loosing & giving electric energy every day 150. Magnetic ring type amplifier is used as 1) inductor 2) simple saturable reactor circuit 3) unsaturated full wave rectifier 4) signal amplifier in communication circuits 151. Copper loss of a transformer is caused by 1) overheating 2) reluctance 3) eddy current loss & hysterisis loss 4) opposition of the conductor comprising the coil turn 152. The % tolerance of the colour code ‘yellow’ is 1) two 2) three 3) four 4) five 153. During discharge _______ is formed on both the & negative plates of lead acid cell 1) lead nitrate 2) lead acetate 3) lead oxide 4) lead sulphate 154. If Ni-cd battery contains high charge, the positive plate contains 1) Pbo2 2) Ni(OH)2 3) NaOH 4) Ni2O2 & Ni2O3 155. The direction of rotation of a three phase induction motor can be changed simply by 1) reversing two of the leads to the motor 2) reversing connections to the starting winding and armature winding together 3) using an addition winding with a capacitor connected across
4)increasing the size of the armature winding 156. The induced emf generated in an inductor 1) opposes the applied voltage 2) boosts the applied voltage 3) creates an induced magnetism 4) creates eddy current in the conductor 157. The ratio of effective valve to an average valve of an alternating quantity is called 1) peace factor 2) r.m.s. valve 3) form factor 4) max. instantaneous value 158. Eddy current can be reduced by 1) reducing the thickness of the conductor 2) replacing the solid core with several insulated thin metal plated 3) applying high frequency a.c. 4) simply using a mica layer between coil & core 159.When a current containing a.c. & d.c. components tries to flow through a capacitor, it blocks 1) a.c. component 2) both a.c. & d.c. components 3) d.c. components 4) neither a.c. nor d.c. components 160.Which one of the following transformer requires a jumper when it is not in use ? 1) power transformer 2) auto transformer 3) RF transformer 4) current transformer 161.Which one of the following generator is not used in a.c. power generation system? 1) shunt wound generator 2) series wound generator 3) split phase generator 4) compound wound generator
162. A series circuit is assured in which the applied voltage is 110 volts at 60 C.P.S. frequency and the capacitance of a condenser is 80μF. Find the capacitive reactance 1) 33.2 Ω 2) 191 Ω 3) 30.9 Ω 4) 49.33 Ω 163.A moving iron instrument can be used for 1) a.c. only 2) d.c. only 3) a.c. & d.c. both 4) neither a.c. nor d.c.
164. When a capacitor, inductor & a resister are connected in series, the effective impedence is equal to __________ 1) (XL + XC)2 2) √(XL + XC) + R 3) [R2 – (XL + XC)2]½ 4) [R2 + (XL - XC)2] ½ 165.If a winding is completely shorted in a transformer 1) it will become cold 2) it will damage the load 3) it will become over heated 4) its performance will be unaffected
166. “When a current carrying conductor is placed in a magnetic field, it tends to rotate” this principle is used in 1) generator 2) motor 3) hotwire instrument 4) rectifier 167. When heavy starting torque is required, we use 1) compound wound 2) shunt wound motor 3) series wound motor 4) d.c. motor 168. The positive and negative plate of a lead acid battery is 1) positive lead oxide & negative pure lead 2) positive lead peroxide and –ve spongy lead 3) positive is carbon rod and –ve is zinc plate 4) positive is pure lead and –ve spongy lead 169. In a constant current charging system, a battery requires constant attention at the end of charging to avoid 1) sulphation of battery 2) spilling of electrolyte 3) evaporation of electrolyte 4) danger of over heating 170. Buckling of the plate can be avoided by using 1) an extra negative 2) by sulphation treatment 3) by charging the battery with very low rate 4) by amalgamating the plate with hydrogen peroxide
176. How can the state of charge of Ni-cd battery be determined? 1) by measuring the S.G. of the electrolyte 2) by a measured charging & discharging 3) by the level of electrolyte 4) by the CCV measured by a voltmeter 177. What happens to the current in a step-up transformer with 1:4 turns ratio? 1) current is reduced by 1:4 ratio 2) current is increased by 1:4 ratio 3) current is reduced by 4:1 ratio 4) current is increased by 4:1 ratio 178.The purpose of providing bottom grooves underneath the plates in a lead acid battery container is to 1) allow for convection of the electrolyte for cooling of the plates 2) ensure that the electrolyte’s quantity and plate area is adequate 3) prevent sediment build up from contacting the plates and causing a short circuit 4) prevent escape of electrolyte but allow 180. Which one of the following has comparatively long service life & low maintenance cost for aircraft 1) lead acid battery 2) dry cell 3) Nickel cadmium battery 4) sodium sulphur battery
171. While diluting the acid to get required S.G. 1) Water is slowly added to acid 2) acid is slowly added to water 3) both are added simultaneously 4) any one 1 or 3
181. If the supply frequency in an aircraft falls more than 10% from the rated value 1) the equipment may be over heated 2) the equipment may be over cooled 3) nothing will happen 4) we cannot predict anything
172. While testing the S.G. of the electrolyte of a nickel cadmium battery, it shows a reading of 1300. That means 1) the battery is fully charged 2) the battery is moderately charged 3) the battery has lesser charge 4) the charging state can’t be predicted
182. In Fleming’s right hand rule, the thumb indicates 1) direction of induced emf 2) direction of magnetic field 3) direction of motion of conductor 4) direction of current flowing in circuit
173. The symptom of a fully charged lead acid battery is 1) free gassing 2) Specific gravity at higher than 1.260 on 3 consecutive reading 3) voltage should be more than 2.1 volt/cell 4) all above may be present 174. The separator used for Ni-Cd battery is 1) nylon coated with cellophane 2) wood packs 3) teak wood
175.
4) glass wool
The neutralising agent for H2SO4 electrolyte is 1) KOH 2) HCL 3) 5% Bicarbonate of soda solution 4) Vinegar
183. The force required to wipe out the residual magnetism is called 1) retentivity 2) magnetising force 3) coercive 4) permeability 184. The brushes connected with commutator is placed 1) 90º away from its neutral position 2) 180º away from its neutral position 3) in neutral position 4) 270º away from its neutral position 185. In two parallel plate capacitor, the capacitance can be increased by 1) increasing the cross section area of the plates 2) increasing the distance between the plates 3) reducing the dielectric constant of dielectric medium
4) all are correct 186. At the end of normal discharge, the internal resistance of a lead acid cell is more than 1) twice as high as it is when fully charged 2) thrice as high as it’s when fully charged 3) half as high as it’s when fully charged 4) one third as high as it’s when fully charged 187. The separators used in lead acid battery have vertical ribs on the side 1) facing the positive plate 2) facing the negative plate 3) facing both the positive & negative plate 4) half part facing positive plate & half part facing negative plate 188. Hydrogen will be released at __ plates and oxygen will be released at ____ plates of a Ni-cd battery 1) negative, positive 2) negative at charging & positive at discharging 3) positive, negative 4) positive ( at discharging) & negative ( at charging) 189. “ Plug in holders” & “clip” type holders are used for 1) heavy high capacity fuses & current limiters 2) circuit breakers 3) switches 4) thermal protectors 190. The most accurate readings from ammeter can be obtained at approximately 1) one third scale deflection 2) half scale deflection 3) one fourth scale deflection 4) nine tenth of scale deflection 191. The sensitivity of a voltmeter is represented by 1) volts per ohm 2) ohms per volt 3) ohms per ampere 4) amperes 192. The purpose of a growler test is to determined the presence of 1) an improper capacitor 2) a shorted armature 3) a broken field frame 4) a broken voltage regulator connection 193. One of the most satisfactory method of overcoming the effect of armature reaction is the use of 1) interpoles 2) shaded poles 3) addition windings 4) additional brushes 194. Which one of the following method is used to increase the output voltage of a d.c. generator? 1) increasing the number of winding in armature 2) increasing the speed of rotation of the armature 3) introducing inter-poles in the field frames 4) introducing shaded pole inside the generator
195. Two spiral conductor are placed face to face, If d.c. current flows through the coils in same manner what will happen 1) attraction 2) repulsion 3) attraction for one alternation & repulsion for the next alternation 4) no affect 196. The eddy current loss of a transformer comes under 1) copper loss 2) iron loss 3) hysterisis loss 4) mechanical loss
197.
A lead acid battery with 12 cells, connected in series (OCV=2)1 volts per cell) supply 10 amp. Current to a load of 2Ω resistance. Find the internal resistance of the battery 1) 0.52Ω 2) 5Ω 3) 2.52Ω 4) 5.52Ω 198. The vibrating reed type of frequency meter works on the principle of 1) mechanical resonance 2) electrical resonance 3) impedance 4) mutual induction 199. If an instrument ( PMMC/MI) having an accuracy of 2% and the actual value of the current to be measured is 200 unit then the meter indication will be 1) 200 to 202 2) 196 to 200 3) 200 to 204 4) 196 to 204 200. The varmeter is used to measure 1) true power 2) reactive power 3) applied power 4) reactive impedance 201. The power factor in a.c. circuit is 1) ratio of true power to apparent power 2) ratio of apparent power to true power 3) ratio of reactive power to ideal power 4) ratio of reactive power to applied power 202. Which one of the following parts is not essential for d.c. generator 1) armature 2) slip ring 3) split ring 4) commutator 203. The voltage coil of the vibrating type voltage regulator is connected________ with the load 1) series 2) parallel 3) in series with the field coil & in series with the load 4) none of these 204. A ‘ continuity tester’ is a 1) voltmeter 2) ammeter 3) ohm meter 4) wattmeter 205. The range of voltmeter can be increased by the use of additional series
1) multipliers 3) shunt
2) voltage resistors 4) none of these
206. The internal resistance of most vented NiCd battery is 1) vary high (grater than few mega ohm) 2) moderately high (approximately few k ohm) 3) very low ( less than 1μΩ per cell) 4) none of these
207. Which of the following material has nearly zero temperature coefficient of resistance 1) Copper 2) Carbon 3) Manganin 4) Mica
208. You have to replace a 1500 Ω resistor in a radio. You have no 1500 Ω resistor but have several 1000 Ω resistor, which you would connect: 1) three in parallel 2) three in series 3) two in parallel and one in series 4) two in parallel 209. When two resistances are connected in series they have 1) same resistance value 2) same voltage across them 3) same current passing through them 4) different resistance value 210. In a parallel circuit, all component must 1) have the same p.d across them 2) have same value 3) carry equal current 4) all 211. The current ratting of a 1 k Ω , ½ W resistor is 1) 2.23A 2) 1A 3) 22.36MA 4) None 212. Four 1)5V cells are connected in parallel . The output voltage is 1) 1.0V 2) 1.5V 3) 6.0V 4) None 213. The emf of a given cell is 1) Distributive 2)Variable 3) Constant 4) Less than terminal P.d 214. A Leclanache cell has 1) A Depolariser 2) A cathode of carbon 3) An Electrolyte of H2SO4 4) Large current capacity 215. A standard cell is primarily used 1) For supplying large currents 2) as a source of energy 3) For providing variable voltage 4) As a secondary standard of voltage 216. A simple potentiometer is correctly called a 1) Current divider 2) Voltage stabilizer
3) Variable resistor
4) Voltage divider
217.According to the commonly used sign convention for voltages : 1. A fall in voltage considered positive 2. A rise in voltage is considered positive 3. IR drop is taken as negative 4. Battery EMF is taken as positive 218. The unit of capacitance is 1) Farad 2) Coulomb 3) Volt 4) Metre 219. The EMF of a fully charged lead Acid cell is about 1) 1.21 2) 2.1 3) 1.8 4) 1.4 220. The neutrons in a nucleus have 1) Positive charge 2) Negative charge 3) No charge 4) 3 electrons 221. The weight of proton is approximately 1) 1000 times than e- 2) 1240 times than e3) 1990 times than e- 4) 1845 times than e222. Direction of current is 1) Same as e2) Opposite to e3) Perpendicular to direction of e- 4) constant 223. When a glass rod is rubbed with silk, the glass rod gives up electrons and becomes 1) Positive charge 2) Negative charge 3) No charge 4) None 224. The larger value of resistance supports 1) More current 2) Less current 3) No effect 4) constant 225.Factors affecting the resistance value is 1) Area 2) Length 3) Temperature 4) All 226. The unit of resistivity is 1) Ohm-metre 2) Ohm 3) Ohmmeter-1 4) None 227. The Ammeter is always connected :1) in series 2) in parallel 3) Anyway 4) None 228. The value of Resistance whole colours are Red, Red and Red is 1) 2k Ω 2) 2)2k Ω 3) 22k Ω 4) 220 229. Tolerance for silver is 1) +5% 2) +10% 3) + 20% 4) +25% 230. The material used for fuse must have 1. low melting point and low specific resistance 2. low melting point and high specific resistance 3. High melting point and low specific resistance 4. None 231. Dielectric strength of a material depends on 1) Moisture content 2) Thickness
3) Temperature
4) All
1) AC 2) DC 3) AC or DC
4) None
232. Relative Permitivity of vacuum is 1) Zero 2) 8.854x10-6 3) Unity 4) None
245. Secondary cell is 1) Charged only 2) Rechargeable None
233. What will happen to an insulating medium of voltage more than the break town voltage is applied on it 1) It will get punchred 2) It will become magnetic 3) It will melt 4) It molecular structure will change
246. The colour of positive plate of full charged Lead Acid cell is 1) Brown 2) Deep chocolate brown 3) Slate Grey 4) None
234. 4 capacitor of 5 μF each are connected in parallel their equivalent capacitance will be 1) 20 μF 2) 10μF 3) 5μR 4)1)25 μF
3)
247. Ratting of the cell is 1) Amp-hour 2) Watt-hour 3) Both 4) None 248. Negative plate of Edison cell is 1) Ni(OH)4 2) Ni(OH)2 3) Cd(OH)2 4) Fe(OH)2
235. Inside the conducting sphere, ___ remains constant 1) Electric flux 2) Electric intensity 3) Charge 4) Potential
249. Sulphation in a lead – Acid Battery occurs due to 1) Trickle charging 2) Incomplete charging 3) Heavy discharging 4) Fast charging
236.
250. Whenever a magnet is quickly brought towards an open circuited stationary coil 1) A current is induced in it 2) Work has to be done 3) EMF is induced in it. 4) Power is spent.
The unit of conductivity is 1) Ohm 2) Ω-m 3) Mho/metre 4) Siemens 237. Lead Acid cell is said to be in good condition if 1. It should not be left in discharging condition for long time. 2. Level of electrolytes should be 5mm above the top of plates 3. Discharging should not be prolonged after the minimum value of the voltage 4. All of the above 238. Alkaline Accumulators are 1) Ni-Fe Battery 2) Ni-Cd Battery 3) Lead-Acid cell 4) Both 1 and 2 239. Positive Plate of Lead-Acid cell during discharge 1)Pb2SO4 2) PbO2 3) PbSO4 4) Pb 240. Life of lead Acid cell is 1) Nearly 1000 charge and discharge 2) Nearly 1250 charge and discharge 3) Five years at least 4) None 241. Specific gravity of lead Acid cell, when it is 50% charged is 1) 1.12 2) 1.22 3) 1.16 4) None 242. Active material of Edison cell are 1) PbO2,Pb, H2So4 2) Ni(OH)4,Cd, KOH 3) Ni(OH)4, Fe, KOH 4) Ni(OH)2, Fe, KOH 243. Average EMF of lead acid cell is 1) 2.1V 2) 2.0V 3) 1.8V 4) 1.2V 244. The input of constant voltage charging system of Battery is
251. The emf induced in a coil depends on 1) the number of its turns 2) the change of flux linked with it. 3) the time taken to change the flux 4) all of the above 252. An emf is induced in the coil whenever flux through it 1) is decreased 2) is increased 3) is abruptly reduced to zero 4) all of the above 253. The direction of the induced emf in a coil may be found with the help of 1) Faraday’s law 2) Lenz’s law 3) Fleming’s left hand rule 4) Steinmetz law 254. The dynamically induced emf in a conductor does not depend on 1) flux density 2) its active length 3) its conductivity 4) its velocity 255. The self-induction of a coil is also called its _____ inertia 1) Electromagnetic 2) Magnetic 3) Both 4) None 256. The coefficient of magnetic coupling between two circuits can have a maximum value of ________ 1) UNITY 2) ZERO 3) TWO 4) NONE 257. Induced emf can be either mutually induced or statically induced 1) TRUE 2) FALSE
4. All of the above 258. The inductance and number of turn of the coil is related with the formula 1) L α N 2) L α N2 3) L = N 4) L= N 259. The Voltage induced in the primary winding of a transformer due to current flowing through it is known as 1) EMF 2) Counter EMF 3) MMF 4) Lenz’s law
260.
The magnetic property of a coil of wire which causes it to induce an opposite emf within the same circuit is called 1) Mutual Inductance 2) Self Induction 3) Permeability 4) Retentivity 261. In transformer following principle is/are involved:1) Conduction 2) Self induction 3) Mutual Induction 4) Both 2 & 3 262. In a step up transformer if input power and output power are same then :1) current in primary = current in secondary 2) current in primary > current in secondary 3)current in primary < current in secondary 4) Voltage in primary > Voltage in secondary 263. The burden of current transformer is expressed in terms of :1. Secondary winding current 2. VA rating of transformer 3. Voltage, current and power factor of secondary winding 4. None of the above 264. The impedance ratio of transformer is defined by the Relation :1) Ns/Np =
(Zs/Zp)
2)Ns/Np= (Zs/Zp)2
3) Ns/Np =
(Zp/Zs)
4) None
265. In a D’Arsonval galvanometer, an iron core is usually used between the permanent magnet pole faces. This is used so that: 1. Flux density in the air gap becomes high thereby a large deflecting torque is produced 2. The effect of stray magnetic fields is reduced 3. Moment of inertia at moving parts becomes smaller 4. None 266. Sometimes, the D’ Arsonval Galvanometer do not use ferromagnetic cores between poles of the permanent magnet. In this case :1. The flux density becomes smaller resulting in low deflecting torque. 2. The dimensions of the moving coil can be made smaller thereby reducing the moment of inertia 3. The magnetic field may not be resulting in a non-uniform scale even it spring control is used
267. A vibration galvanometer is tuned 1. by changing the length and tension of vibration coil 2. by attaching weight to the vibrating coil 3. by changing its damping constant 4. All of the above 268. In a series type ohmmeter the zero adjustment should be done 1. by changing the value of series resistance 2. by changing the value of shunt resistance connected across the meter movement 3. by changing the both series as well as shunt resistance 4. by changing the battery voltage 269. A meggar is used for measurement of 1) low valued resistance 2) Medium valued resistance 3) High valued resistance, particularly insulation resistance 4) All of the above 270. The controlling torque in a meggar is provided by 1) Springs 2) Weight attached to the moving system 3) Does not need any controlling torque 4) None of the above 271. Thermocouple instruments can be used for a frequency range 1) Up to 100 Hz 2) Upto5000Hz 3) Up to 1MHz 4) 50 MHz and above 272. Voltmeter measures 1) Voltage 2) EMF 3) Terminal potential 4) All of the above 273. An Electrostatic voltmeter draws a small value of current on d.c. 1. Under steady state condition respective of the applied voltage 2. When switched ON irrespective of the applied voltage 3. When measuring low voltages 4. When measuring high voltages 274. The scale of D’Arsonval metres are : 1) cramped at the beginning 2) cramped at the end 3) Uniform 4) Non uniform 275. Ohmmeter is used to measure 1) Insulation Resistance 2) Circuit resistance 3) Continuity of the circuit 4) Both 2 and 3 276. A meter is said to be more sensitive when for full scale deflection : 1) It takes less current 2)It takes more current 3) It requires a multiplier or a shunt 4) None
277. In a megger the controlling torque is provided : 1) Coil springs 2) Current flow in the control coil 3) Eddy current 4) Mechanical control method
287. The line representing the critical resistance of a dc generator _________ its O.C.C 1) intersect 2) does not intersect 3) just touches 4) runs parallel to
278. Aircraft DC generator is a : 1) Compound generator 2) Series generator 3) Shunt generator 4) Either 1 or 3
288. The __________ dc generator has the poorest voltage regulation 1) Over-compound 2) compound 3) Shunt 4) Series
279. For AC generators having high field current; 1)Series generator is used 2)Vibrating contact regulator is used 3) Carbon pile regulator is used 4) Compensating winding is used in regulator
289. Which of the following generator provides approximately constant voltage from no-load to full load 1) Series 2) Shunt 3) compound 4) Over compound
280. In a type of DC generator, when load is increased, voltage increases and when the load is decreased, voltage also decreases, the generator can be 1) Shunt generator 2) Differential compound generator 3) Compound generator 4) Series generator 281. The direction of current flow in a generator is determined by : 1) Left hand rule of generator 2) Faraday’s Law 3) Lenz’s law 4) Grip rule 282. The armature conductors of a 6 pole lap wound dc generator are divided into, ______ parallel paths 1) 2 2) 3 3) 6 4) 4 283. In a long shunt compound wound generator, the shunt field is connected in parallel with 1. Armature 2. Series field 3. Parallel combination of armature and series field 4. Series combination of armature and series field 284. The overall efficiency of a dc shunt generator is maximum when its variable loss equal ________ loss. 1) Stray 2) Iron 3) Constant 4) Mechanical 285. In a d.c. generator, the main function of compensating windings is to 1. Assist in commutation 2. Reduce demagnetising effect of Armature reaction 3. Reduce distorting effect of armature reaction 4. Eliminate reactance voltage 286. The O.C.C of a d.c. generator is also called its ________ characteristics 1) Internal 2) Magnetic 3) External 4) Performance
290. The armature torque of a dc motor is a function of its 1) pole flux 2) Armature current 3) Speed 4) Both 1 and 2 291. A d.c. series motor is best suited for driving 1) Latches 2) Heavy machine tools 3) Cranes and hoists 4) Shears and punches 292. The speed of a dc motor can be controlled by varying 1) its flux 2)Armature circuit resistance 3) Applied voltage 4) All of the above 293. The level of compounding in a cumulatively-compound d.c. Generator is usually adjusted by: 1) alternating series field current 2) changing shunt field current 3) connecting it long-shunt 4) connecting it short – shunt 294. An electric motor is used for 1. Generating power 2. Changing mechanical energy to electrical 3. changing electrical energy to mechanical 4. increasing the energy put into it 295. Capacitor is used to 1) block AC 2) block DC 3) Both 4) none of the above 296. Four inductor of 2μH is connected in series is the equivalent inductance 1) 2μ h 2) ½ μH 3) 8μH 4) None 297. Capacitive reactance Xc is measured by relation 1) Xc = ½ πf C 2) Xc=2 πf C 3) Xc= 1/2 π C 4) None
298.
Capacitors with solid dielectric materials are used because 1. they give a reduce dielectric loss 2. they are smaller is size as compared to air capacitor
3. they have lower capacitance value as compared to air capacitor 4. None of the above
1) 4:1
2) 2:1
3) 1:2
4) 1:4
299. Which one of the following is passive component 1) Resistor 2) Capacitor 3) Inductor 4) All of the above
309. A 200 W, 230 V lamp is connected across 115 V supply. The lamp will draw power 1) slightly more than 50 watts 2) slightly less than 50 watts 3) exactly 100 watts 4) exactly 50 watts
302. An electric current is 1) random movement of electrons in a conductor. 2) movement of free electrons predominately in one direction. 3) pressure difference between two poles. 4) the power that causes drift of electrons.
310. A permeable substance is one 1) through which the magnetic lines of force can pass very easily 2) which is a strong magnet 3) which is a bad conductor 4) none of these
303. Ampere- second could be the unit of :1) e.m.f. 2) charge. 3) power 4) energy
311. Soft magnetic materials have 1) high permeability & low coercive force 2) low permeability & high coercive force 3) high residual magnetism 4) low resistivity
304. The minimum requirements for causing flow of current are:1) a voltage source, a resistor and a switch. 2) a voltage source & a conductor. 3) a power source and a bulb 4) a voltage source, a conductor, an ammeter and a switch. 305. Pure metals generally have :1) high conductivity and low temperature coefficient. 2) high conductivity and large temperature coefficient. 3) low conductivity and zero temperature coefficient. 4) low conductivity and high temperature coefficient. 306. With the rise in temperature, the temperature coefficient of resistance :1) remains unaffected 2) increases. 3) decreases. 4) none of these. 307. Temperature coefficient of resistance is defined as:1) increase in resistance per ohm per degree C 2) increase in resistance per degree C 3) decrease in resistance per ohm per degree C 4) the ratio of decrease in resistance per degree C to the resistance at 0 degree C 308. Which of the following quantities are the same in all parts of a series circuit? 1) voltage 2) power. 3) current. 4) resistance. 307. Two resistors R1 & R2 give combined resistance of 4)5 ohm when in series and 1 ohm when parallel the resistances are 1) 2 ohms & 2.5 ohms 2) 1 ohm & 3.5 ohms 3) 1.5 ohms & 3 ohms 4) 4 ohms & 0.5 ohms 308. The ratio of resistances of a 100 Watt, 220 V lamp to that of a 100 Watt, 110 V lamp will be, at the respective voltages
312. When a piece of iron is placed in a magnetic field 1) there will be no effect on the magnetic field 2) the magnetic lines of force will bend away from the piece 3) the magnetic lines of force will bend away from their usual paths so as to pass through the piece 4) none of these 313. The magnitude of force acting on a current carrying conductor placed in a magnetic field is independent of 1) flux density 2) length of conductor 3) cross-sectional area of conductor 4) current flowing through the conductor 314. The field at any point on the axis of a current carrying coil will be 1) perpendicular to the axis 2) parallel to the axis 3) at an angle of 45 degree with the axis 4) zero 315. The property of a material which opposes the production of magnetic flux in it is known as 1) mmf 2) reluctance 3) permeance 4) permittivity 316. The magnitude of induced emf in a conductor depends on 1) amount of flux cut 2) amount of flux linkage 3) rate of change of flux linkage 4) flux density of magnetic field 317. The principle of dynamically induced e.m.f is utilized in a 1) choke 2) transformer 3) generator 4) battery 318. A coil with a certain number of turns has a specified time constant. If the number of turns is doubled, its time constant would
1) remain unaffected 2) becomes doubled 3) becomes one fourth 4) get halved
3) Reduces radio interference 4) All of the above
319. In a step up transformer, the power output is same as primary input power neglecting the losses, but 1) current is increased in secondary 2) current increases & voltage decreases in secondary 3) current decreases & voltage increases in secondary 4) current & voltage both increase in secondary
328. Many of the larger transport a/c have been equipped with AC electrical system. The reason is 1) Easier to install 2) Less maintenance required 3) More efficient 4) All of the above
321. The amount of current required to produce a full scale deflection of the indicating needle is known as 1) stability of the instrument 2) sensitivity of the instrument 3) selectivity of the instrument 4) none of these 322. Thermal circuit breakers 1) can not be reset until the temperature has returned to normal 2) it can be reset before the temperature reaches normal 3) can be reset at any time 4) none of these is correct 323. A resistor coloured red as per the body end dot system is of 1) 33000 ohms 2) 3300 ohms 3) 22000 ohms 4) 2200 ohms 324. During flight, when more power is needed the generator voltage will 1) Remain at a constant value, however the current flow will increase 2) Automatically decrease because of the greater current flow 3) Remains at a constant value, the current will also remain at a constant value 4) Increase at a steady value in order to restrict the current flow 325. All resetable circuit breakers 1) Should open the circuit irrespective of the position of the operating control when overload exists 2) Should open the circuit irrespective of the position of the operating control when a circuit fault exists 3) Are referred to as trip-free circuit-free circuit breakers 4) All of the above 326. Circuit breakers are located 1) Generally far from the power source 2) Close to the power source 3) At any location compatible to the particular unit 4) So as not to be exposed to heat of any kind 327. Generator inter poles 1) Improve generator output 2) Prolong the life of the brushes & commutator
329. A lead-aid battery with 12 cells connected in series (no-load voltage=2)1 volts per cell ) furnishes 10 amperes to a load of 2 ohms resistance. The internal resistance of the battery in this instance is 1) 0.52 Ω 2) 2.52 Ω 3) 5 Ω 4) 0.25 Ω 330. If electrolyte from a lead-acid battery is spilled in the battery compartment, which procedure should be followed? 1) Apply boric acid solution to the affected area followed by a water rinse 2) Rinse the affected area thoroughly with clean water 3) Apply sodium bicarbonate soul to the affected area followed by a water rinse. 4) None of these 331. If residual magnetism of a shunt generator is destroyed accidentally, it may be restored by connecting its shunt field:1)to earth 2)to an a.c. source 3)in reverse 4)to a d.c. source 332. Transformer cores are laminated in order to 1)simplify its construction 2)minimise eddy current loss 3)reduce cost 4)reduce hysterisis loss 333. The measure of how well the flux of the primary is coupled into the secondary is called:1)mutual inductance 2)self-inductance 3) coefficient of coupling 4) coefficient of excitation 334. The speed of an induction motor put in aircraft, with 4 poles and 5% slip is 1)12000 rpm 2)24000 rpm 3)11400 rpm 4)22800 rpm 335. The speed of rotor of a synchronous motor, with 4-poles, in aircraft 1)12000 rpm 2)24000 rpm 3)11400 rpm 4)22800 rpm 336. In order to synchronize two or more alternators, they should have 1)same phase -sequence 2)same frequencies 3)same voltages 4)all of these 337. A voltage drop is 100 volt across a 100 ohms resistance delivers
1)10,000 watts 3)100 watts
2)1000 watts 4)10 ampere
338. Time constant of a RC circuit is:1)R x C seconds 2)R / C seconds 3)C / R seconds 4)R + C seconds 339. Number of alternations in 400 Hz a.c. is 1)200 2)400 3)600 4)800 340. If electrolyte from a lead-acid battery is spilled in the battery compartment, which procedure should be followed? 1) Apply boric acid solution to the affected area followed by a water rinse 2) Rinse the affected area thoroughly with clean water 3) Apply sodium bicarbonate soul to the affected area followed by a water rinse. 4) None of these 341. A fully charged lead acid battery will not freeze until extremely low temperatures are reached because. 1) The acid is in the plates, thereby increasing the specific gravity of the solution 2) Most of the acid is in the solution 3) Increased internal resistance generates sufficient heat to prevent freezing 4) None of these 342. What determines the amount of current which will flow through a battery willable it is being charged by a constant voltage source 1) The total plate area of the battery 2) The state of charge of the battery 3) The ampere- hour capacity of the battery 4) None of these 343. The method used to rapidly charge a nickel cadmium battery utilizes 1) Constant current and constant voltage 2) Constant current and varying voltage 3) Constant voltage and varying current 4) None of these 344. The purpose of providing a space underneath the plates in a lead acid battery container is to 1) prevent sediment build up from courting the plates and causing a short circuit 2) allow for convection of the electrolyte in order to provide for cooling of the plates 3) ensure that the electrolyte quantity ratio to the number of the plates area is adequate 4) none of these 345. The servicing and charging of nickelcadmium and lead acid batteries together in the save service area is likely to result in 1) Normal battery service life 2) Increased explosion and / or fire hazard 3) Contamination of both types of batteries 4) None of these
346. Nickel-cadmium batteries which are stored for a long period of time of time will show a low liquid level because 1) Electrolyte evaporates through the vents 2) Of current package form individual cells 3) Electrolyte becomes absorbed into the plates 4) None of these 347. What may result it water is added to nickel cadmium battery when it is not fully charged ? 1) Excessive electrolyte deletion 2) Excessive spewing is likely to occur during the charging cycle 3) No adverse effects since water may be added any time 4) None of these 348. In nickel cadmium battery, a rise in celltemperature 1) Causes an increase in internal resistance 2) Causes a decrease in internal resistance 3) Increases cell voltage 4) Has no effect 349. When a charging current is applied to a nickel-cadmium battery, the cells gas only 1) Towards the end of the charging cycle 2) When the electrolyte level is low 3) It they are defective 4) None of these 350. Transfer of electrical energy from one conductor to another without the aid of electrical connections 1) Is called induction 2) Is called air gap transfer 3) Will cause excessive arcing and heat 4) Is impractical 351. Effective value of a sine wave is approximately 1)1.414 x Peak Value 2)Peak Value / 1)414 3)0.636 x Peak Value 4)Peak Value / 0.636 352. Of the following, which will oppose any change in current 1)resistance 2)capacitor 3)inductor 4)all of these 353. Equivalent resistance, when resistors of 2, 4 and 8 ohms are in parallel 1) 14 ohms 2) 7 / 8 ohms 3) 8 / 7 ohms 4) 2 ohms 354. The effective voltage of a a.c. sine wave 200 peak-to-peak, is approximately 1)70.7 volt 2)141.4 volt 3)63.7 volt 4)127.4 volt 355. 1)line 2)line 3)line 4)line 356.
In delta connection current =phase current voltage =phase voltage current
1)line current =1.73 x phase current 2)line voltage =phase voltage 3)line current =phase current 4)phase voltage =1.73 x line voltage 357. Dielectric strength of a material depends on 1)thickness 2)temperature 3)moisture content 4)all of these 358. The direction of rotation of a single-phase motor can be reversed by 1) Reversing connections of both windings 2) Reversing connections of starting winding 3) Using a reversing switch 4) Reversing supply connections 359. If a single phase induction motor runs slower than normal, the more likely defect is 1) Improper fuses 2) Shorted running winding 3) Open starting winding 4) Worn bearing 360. The voltage required to rupture the given thickness of a dielectric material for capacitor is termed as 1) Dielectric strength 2) Dielectric constant 3) Capacity of a capacitor 4) Ability of a conductor to hold the charge 361. When relatively high capacitance is required in a small capacitor, we use 1) Ceramic capacitor 2) Paper capacitor 3) Electrolytic capacitor 4) Mica capacitor 362. A circuit is said to be in resonance when 1) inductive reactance= capacitive reactance 2) inductive reactance >capacitive reactance 3) inductive reactance
367. Iron loss is the combination of 1) Copper and eddy current loss 2) Hysterisis and Eddy current loss 3) Copper & Hysterisis loss 4) Copper & Mechanical loss 368. In synchronous motor, damper winding is provided in order to 1) Stabilize rotor motion 2) Suppress rotor oscillations 3) Develop necessary starting torque 4) Both (2) & (3) 369. While running, a synchronous motor is compelled to run at synchronous speed because of 1) Damper winding in its pole faces 2) Magnetic locking between stator & rotor poles 3) Induced e.m.f in rotor field winding by stator flux 4) Compulsion due to Lenz's law 370. The direction of rotation of a Synchronous motor can be reversed by reversing 1) Current to the field winding 2) Supply phase sequence 3) Polarity of rotor poles 4) None of the above 371. The moving system of an indicating type of electrical instrument is subjected to 1) A deflecting torque 2) A controlling torque 3) A damping torque 4) All of the above 372. The damping force acts on the moving system of an indicating only when it is 1) Moving 2) Stationary 3) Near its full deflection 4) Just starting to move 373. The most efficient form of damping employed in electrical instruments is 1) Air friction 2) Fluid friction 3) Eddy currents 4) None of these
364. In a constant current charging system, a battery requires attention at the end of charge to avoid 1) Sulphation of battery 2) Spilling of electrolyte 3) Evaporation of electrolyte 4) Danger of overheating
374. The meter that is suitable for only direct current measurement is 1) Moving-iron type 2) Permanent magnet type 3) Electrodynamics type 4) Hot wire type
365. 66. While measuring the value of resistance, connected in a circuit at least one end of resistance is disconnected in order to avoid 1) reading the resistance of series path 2) damage of resistance in parallel path 3) damage of resistance in series path 4) reading the resistance of parallel path
375. Damping torque in an indicating instrument is always 1) Opposite to deflection torque 2) In the same direction as the controlling torque 3) Opposite to the direction of motion of moving system 4) Opposite to the controlling torque
366. In how many ways, 3-identical resistors can be connected? 1) 1 2) 2 3) 3 4) 4
376. The main purpose of using instrument transformer in a.c. measurements is to 1) Reduce the possibility of shock
2) Extend the range of ac instruments 3) Provide higher transformation ratio 4) Eliminate instrument correction
inductive reactance capacitance capacitive reactance
377. The hot wire ammeter 1) is used only for d.c. circuits 2) is a high precision instrument 3) is used only for ac circuits 4) reads equally well on d.c. and /or circuit
386. With the rise in temperature, the opposition offered to current flow in the semi conductor: 1) in creases 2) decreases 3) remains unaffected 4) can’t predicated
378. The power loss due to ohmic heating in a transformer is called 1) magnetic loss 2) hysteresis loss 3) copper loss 4) eddy current loss 378. The capacity of a capacitor is dependent on 1) plate area 2) thickness of dielectric 3) dielectric constant 4) all of the above 379. Multimeter may measure 1) current in mili-amps 2) voltage in volt 3) resistance in ohm 4) all of the above 380. In a R-L-C series circuit, at a frequency below the resonance value, the circuit’s behaviour is 1) capacitive 2) inductive 3) resistive 4) none of the above 381. Which will oppose any change in voltage 1) inductor 2) capacitor 3) resistor 4) both (2) and (3) 382. The outer most orbit of an atom of a semi conductor has : 1) 4 electrons 2) more than 4 electrons 3) less than 4 electrons 4) protons 383. The force between two stationary charged particles is _______ force 1) electromotive 2) electrostatic 3) magneto motive 4) centripetal
1)
384. Unit of capacitance is : 1) micro farad 2) farad 3) mho 4) both (1) & (2) 385. Coulomb per volt is the unit of – inductance
387. Which one is common in all parts of a series circuit ? 1) current 2) power 3) resistance 4) voltage 388. A voltage drop 200 V across 50 ohm resistance delivers power of 1) 10 KW 2) 1 KW 3) 0.8 kW 4) 0.1 KW 389. Time constant of RC circuit is : 1) R X C 2) R/C 3) C/R 4) R + C 390. The area of hysteresis curve is a measure of 1) magnetic flux 2) MMF per cycle 3) Pemeance 4) Energy loss per cycle 391. Magnetism of a magnet can be destroyed by : 1) heating 2) inductive action by other field 3) hammering 4) all of the above 392. The number of positive alternations of aircraft electrical system voltage is equal to : 1) 200 2) 400 3) 600 4) 800 393. The sensitivity of the D’Arsonval meter movement is expressed in terms of 1) ampere 2) volt 3) either ampere or volt 4) neither (1) nor (2) 394. Of the following, which will resist any change in current ? 1) inductor 2) capacitor
3) resistor 4) all of the above 395. The effective value (RMS) of a sine wave is nearly 1) √2 X Vp 2) Vp X 1/√2 3) 0.636 X Vp 4) Vp / 0.636 where Vp – peak value 396. Power factor is the ratio of 1) active power to reactive power 2) real power to apparent power 3) reactive power to VA power 4) actual power + VAR power 397. The equivalent capacitance value, when three capacitor having same value, are connected in series, is : 1) 75 MF 2) 25 MF 3) one third of each value 4) 3 times the value of the capacitor 398. The value of resistance between two vertices, when three equal resistance are connected in delta form, is 1) 1/3 x X 2) 2/3 x X 3) 3/2 x X 4) 1/4 x X where X - > the value of each resistor 399. The colour of the fourth band of the carbon resistor indicates its : 1) current rating 2) voltage rating 3) ohmic value 4) tolerance 400. The device which converts one form of energy into other form is called 1) motor 2) generator 3) transducer 4) transformer and battery 401. The direction of the rotation of dc. Motor can be reversed by : 1) reversing the field current 2) reversing armature current 3) either (1) or (2) 4) reversing the input terminals 402. The commutator segments are insulated from one other by 1) thin sheet of mica 2) using riser 3) hard drawn copper 4) pig tail 403. Battery charger may have generally 1) dc generator/ac generator as source 2) transformer primary multi tapped 3) transformer with rectifier unit
4) selector switch only 404. A device which converts ac into dc and vice versa is : 1) Inverter 2) rectifier 3) alternator 4) commutator 405. A d.c. generator consists of : 1) field frame assembly 2) armature assembly 3) commutator and brush assembly 4) all of the above 406. Degree of compounding means the effect of 1) series field on terminal voltage 2) terminal voltage on series field 3) generated voltage on terminal voltage 4) shunt field on series field 407. If terminal voltage is equal to full load voltage, generator is called : 5) flat compound 6) differentially compound 7) cumulatively compound 8) either (2) or (3) 408. In compound wound generators _____ field coil is of ____ conductor with ____ turns. series, thick, a few series, thin, a few series, thin, many series, thin, many 411. The effect of armature reaction may result in pitted commutator surface enough wear on brushes reduction in output voltage all of the above 412. The _____ motor is not started without mechanical load : d.c. series induction shaded pole capacitor start 413. For a d.c. motor which of the following is wrong copper losses in field and armature winding hysteresis losses in armature core hysteresis losses in electro magnet eddy current losses in magnetic core 414. The part of a d.c. motor which change the current flow from one wire to another is : Yoke 2) armature 3) brushes 4) commutator 415. In aircraft, frequency of a.c. supply is : 800 Hz 2) 400 Hz 3) 200 Hz 4) 100 Hz
1)
416. For the given shape of coil, the inductance value depends on number of turns cross sectional area type of core all of the above
427 At resonance, for the tank circuit, ________ is maximum Impedance current both (1) and (2) neither (1) nor (2)
417. The starting winding of single phase induction motor is placed in : rotor 2) stator 3) armature 4) field
428 In case of Ni/cd battery, during discharge _____ remains unchanged voltage of cell sp. gravity amount of active material at cathodes amount of active material at +ve plates
418.
The single phase motor is : 1) Inherently not self starting
ting nly one winding in one direction only
419. In reed type frequency meter, the reed with natural frequency of 200 cps is marked : 100 cycles 2) 200 cycles 3) 150 cycles 4) 400 cycles 421. In case of discharge of lead acid battery 1) formation of PbSO4 on both plates occurs 2) sp. gravity of electrolyte increases 3) cell emf. Increases 4) colour of positive plates becomes chocolate deep brown 422 In completely charged condition, the cell emf. of lead acid is nearly : 1) 2.2V 2) 1.5V 3) 1.25V 4) 1.75V 423 acid cell is : spongy lead lead peroxide electrolyte all of the above
The active component of pb-
424. The sump jar is used in installation of battery in a/c for the purpose to prevent the corrosion in a/c structure strengthen the electrolyte to purify the electrolyte to make the electrolyte thick 425. ____ is one of the factor of thermal run away of ni/cd (Nickel / Cadmium) cell damaged layer of cell phane material exothermic reactions at electrodes (plates) 30% dilute KoH by volume both (1) and (2) 426. Which of the following is correct for Ni/cd battery its initial cost is relatively high current delivering capacity less it can not be discharged to zero voltage level for same capacity of pb acid, its weight is high
429 Horizontal ribs in Pb-acid cells provide the cavity for electrolyte provide the cavity for fallen material enhance the rate of reaction enhance the delivering rate of current 430 During the installation of battery in a/c, _____ terminal is connected first and in order to____: positive, complete the circuit negative, complete the circuit positive, avoid the accidental short negative, avoid the accidental short 431 _______ ribs of battery in order to circulate the electrolyte and _____ ribs in order to accumulate the fallen material are made : horizontal, vertical horizontal, horizontal vertical, horizontal vertical, vertical 432 When electrolyte is prepared : chemical should be added drop wise water should be added either (1) or (2) neither (1) nor (2) 433 In case of Ni/cd cell or battery, in order to maintain the electrolyte level mineral water can be added 2) tap water can be added during any state of charge 3) distilled water should be added after 2hrs. later than completion of full charge 4) distilled water should also be added without confirmation of its full charge 434 What do you observe when Ni/cd cell is kept on normal load ? decrease in electrolyte level significant reduction in OCV fall in CCV both (1) and (3) 435 What precautions should a technician take during storage of battery expected to used shortly battery should be always charged
storage house should be well vertillated 3) detrimental material and open flame should not be in vicinity of batteries all of the above 436. Which test is done with a/c battery ? 1) electrical leakage test 2) electrolyte leak test 3) capacity test 4) all of the above 437. The capacitor can be used 1) to produce the starting torque 2) to filter the wanted signal 3) to enhance the voltage induced in magneto 4) all of the above 438. The current through the capacitor leads its voltage drop by an angle of : 90 degree 60 degree 30 degree 45 degree 439. In elementary d.c. generator, if no of coil is increased induced emf. will increase 2) no. of ripple frequency will increase, resulting in steady dc ripple will decrease both (2) and (3) 440. Which of the following facts related to elementary d.c. generator is incorrect? 1) during the rotation, for instant, when coil’s plane remains along MNA induced emf is minimum 2) in above case, when coil’s plane is along MA, induced emf is maximum 3) direction of current flow in coil is given by lenz’s law 4) direction of polarity of induced emf is given by Fleming left hand rule 441. The operating principle of generator is based on faraday’s law of electrolysis faraday’s law of electromagnetic induction lez’s law child’s law 443. In electrical measuring instrument (D’Arsonval meter), most effective damping torque is given by eddy current fluid friction pneumatic friction all of the above 444. Damping torque is essential in order to : bring the pointer after less no. of oscillation to see the reading easily and get-accurate value both (1) and (2) none of the above
445. Which of the following has/have linear (even) scale PMMC, Dynamometer wattmeter Moving iron ammeter Both (1) and (2) 446. Which of the following measure ac current only PMMC Dynamometer ammeter Moving coil ammeter Induction ammeter 447. Energy meter has scale pointer gear train both (1) and (2) 448. Which of following is correct ? When θ- deflection , I – Current, V – Voltage, W – Watt. 1) θ α I for PMMC 2) θ α V for PMMC 3) θ α W for dynamometer watt meter, 4) all of the above 449. The method to obtain the residual magnetism in self excited, in d.c. generator is known as field flashing commutation excitation rectification 450. Reason behind large movement of pointer (about 270 degree) over the scale of D’Arsonval meter field is radial deflection proportional to electrical quantity eddy current damping both (1) and (2) 451. In a step up transformer, the power output is same as primary power neglecting the losses, but ______ in secondary current increases current increases but voltage decreases current decreases and voltage increases current and voltage both increase
452. In practical transformer, the coefficient of coupling is : 1) less than 1 3) equal to 1 100
2) more than 1 4) equal to nearly
453. Turn ratio of transformer is equal to ratio of θ2 & θ1 V2 & V1 E2 & E1 E1 & E2
When θ (θ1, θ2) – flux, V (V1, V2) – Terminal voltage, E (E1, E2) – induced in winding 454. The induced emf. In primary and secondary of a transformer are 1) equal in magnitude 2) in same phase 3) 180 degree out of phase with applied signal 4) both (2) and (3) are correct 455 The rotational (frictional) losses do not occur in 1) Transformer 2) dc-generator 3) Static inverter 4) both 1 & 3 456. The D’Arsonval meter movement may be used to measure 1) current only 2) voltage only 3) resistance only 4) current, voltage and resistance 457. The shunting effect occurs in ______ generally 1) ammeter 2) voltmeter 3) wattmeter 4) none of the above 458. In the circuit given below
1) 2) 3) 4)
I I I I
(R1+R2+R3) (R1+R2+R3) (R1+R2+R3) (R1+R2+R3)
– E2 + E1 = 0 + E1 - E2 = 0 + E1 + E2 = 0 – E1 - E2 = 0
459. Kirchoff’s laws are applicable to 1) ac only 2) dc only 3) both (1) and (2) 4) none of the above 460. According to Ohm’s law for resistor 1) V α I 2) V=RI 3) V=KIn 4) Both (1) and (2) where n=1/2 461. The retentivity of magnetic material means 1) residual magnetism 2) ability to keep residual magnetism 3) ability to remove the residual magnetism 4) ability to get magnetism 462. The soft iron piece is used as electromagnet because it has ____ retentivity and _____ permeability 1) low, high 2) high, low 3) low, low 4) high, high
463. In self excited dc-generator, electromagnet instead of permanent magnet is used for necessary field 1) to change the field strength as per requirement 2) because with time strength of p. magnet decreases 3) because its size is less 4) all of the above 464. In generator, induced emf depends on 1) no of turns 2) field strength (¢) 3) speed of armature 4) all of the above 465. Very high insulation resistance of electric cable shall be measured by 1) high range ohmmeter 2) meggar 3) ammeter 4) both (1) and (2) are correct 466. How can it be determined if a transformer winding has some of its primary turns shorted together? 1) the output voltage will be low 2) it will not function 3) it will get hot in normal operation 4) its input current will be less 467. Aircraft fuse capacity is rated in 1) volt 2) ohm 3) microfarad 4) all of the above are incorrect 468. Which of the following is correct? 1) an electromechanical s/w with fixed core is called solenoid 2) an electromechanical s/w with movable core is called relay 3) an electromechanical s/w with fixed core is called relay 4) all of the above 469. An instrument that works as ohmmeter, ammeter and voltmeter is known as 1) wattmeter 2) megger 3) frequency meter 4) avometer 470. A circuit is said to be resonant when 1) XC = XL 2) XC < XL 3) XC > XL 4) XC & XL are minimum 471. The dielectric strength is measured in terms of 1) breakdown voltage per unit thickness 2) breakdown voltage 3) current
4) watt 472. Why are the iron cores of most induction coils laminated 1) to increase core reluctance 2) to increase core permeability 3) to reduce the effect of eddy current 4) all of the above are wrong 473. Most of circuit breaker used in a/c is 1) resettable 2) non resettable 3) based on principle of bimetallic 4) thermally operated 474. A/c circuit breakers 1) can be used as controlling device sometimes 2) can be used as protective device 3) are mostly thermally operated 4) both (1) and (2) 475. The range of voltmeter and ammeter can be increased by _____ and _____ respectively 1) shunt, multiplier 2) shunt, shunt 3) multiplier, shunt 4) multiplier, multiplier 476. Which of the following is correct? 1) voltmeter may be connected across source 2) ammeter may be connected across source 3) ammeter is connected in parallel 4) voltmeter is connected in series 477. ____/ __ is the symbol of 1) SPDT 2) SPST 3) DPST 4) DPDT 478. In dc motors 1) net emf = applied voltage – counter emf 2) net emf = counter emf – applied emf 3) net emf = counter emf 4) net emf = applied voltage 479. The speed of series wound dc motors can be changed 1) by field diverter above normal value 2) by field diverter below normal value 3) either (1) and (2) 4) none of the above 480. Derating _ 1) multiplier, 2) multiplier, 3) multiplier, 4) multiplier,
factor is a ____ in order to establish capacity of s/w suitable voltage to the circuit current value for CB current rating of fuse
481 . The example of intermitted relay switch is ___ 1) battery relay switch 2) starter relay switch 3) both (1) and (2) 4) neither (1) nor (2)
482 The sole purpose of a commutator in dc generator is to 1) increase output voltage 2) reduce sparking at brushes 3) provide consistency in output 4) convert ac into dc 483. High frequency voltage is used in a/c in order to 1) reduce the weight of motor 2) reduce the speed of motor 3) increase the efficiency of motor 4) all of the above 484. Which of the following is incorrect? 1) current transformer (CT) is accurate current ratio transformer 2) CT is step up transformer 3) When in operation its secondary should not be open 4) CT may be used to measure voltage with low range instrument 485. Basic difference between CT and PT will be that 1) PT is ratio transformer 2) PT is ac operated device 3) PT is very low power instrument transformer 4) PT is step down transformer 486. In auto transformer 1) both windings are electrically isolated 2) power is transferred by induction only 3) there is saving of copper material 4) it is not power transformer 487. Power is given by _____ in 3-phase alternator 1) √3 VL IL 2) √3 VP IP 3) √3 VP IL 4) √3 VL IP 488. If after starting, one connection to 3-phase induction motor is accidentally broken 1) motor will always continue to rotate 2) motor will continue to rotate if load on motor is less than 1/3rd of full load 3) motor will continue to rotate in case of full load only 4) motor will never rotate 489. Which of the motors is not self starting 1) two phase induction motor 2) series wound dc-motor 3) 3 phase induction motor 4) 1 – phase induction motor 490. If the speed of induction motor is predicted to be synchronous 1) relative speed of rotor w.r.t field is zero 2) % slip is zero 3) net torque is zero 4) all of the above are correct 491. The direction of ______ motor can not be reversed 1) dc series
2) 3 - phase induction 3) capacitor start induction 4) shaded pole induction 492. Which one is incorrect ? 1) in 3 phase star (λ) connected alternator line voltage = √3 x phase voltage 2) in 3 phase induction motor, three windings are 120 degree electrically displaced 3) 3-phase motor or multiphase motor, there is synchronous field 4) TR-unit converts dc into ac 493. Which of motors has the highest starting torque for same power output 1) series dc motor 2) cumulatively comp motor 3) shunt wound dc motor 4) differentially comp motor 494. Series dc motors are used in a/c 1) as engine starter 2) for raising or lowering landing gear 3) for cow flaps 4) all of the above 495. When cell is loaded, the terminal voltage, Vt 1) is less than emf of cell by ‘Ir’ drop 2) is equal to cell’s emf 3) is greater than emf by ‘Ir’ drop 4) all of the above are correct 496. Fact related to primary cell is that 1) cell can not be recharged satisfactorily 2) negative plates of cell does not deteriorates when on load 3) material (active) does not go into electrolyte 4) positive plates of cell deteriorates effectively 497. Fact relating to secondary cell is that 1) active material does not go into solution 2) it can be recharged and discharged many times before complete deterioration 3) active material undergoes chemical changes during charging and discharging 4) all of the above are correct 498. Sulphation in cell means 1) to charge the cell at slow rate 2) to discharge it at slow rate 3) layer of active material becomes hard and useless 4) boiling of electrolyte 499. One more negative plate (in Pb acid cell) than +ve plates is used in order to 1) prevent +ve plate from warping 2) increase the cell potential 3) increase the cell capacity 4) decrease the cell’s internal resistance 500. Cells are rated as 1) AH 2) voltage 3) watt
4) both (1) and (2) 501. Factors affecting the capacity of cell are 1) rate of discharge or recharge 2) no of plates (area of plates) 3) density of electrolyte and active material mass 4) all of the above 502. Ni / Cad cell is advantageous over Pb-acid cell from ______ view point 1) low maintenance cost and long service life 2) short recharge time and good reliability 3) excellent reliability and good starting ability 4) all of the above 503. Your observations relating to Ni / Cad cell may be 1) release of O2 from –ve plates and absorption of O2 by +ve plates during charging 2) formation of gas (mixture of H2 & O2) towards end of charging process 3) sp. gravity unchanged 4) all of the above 504. Alkaline solution is neutralized by using 1) vinegar 2) lemon juice 3) boric acid 4) any one of the above 505. Which one is the polar capacitor? 1) Oil 2) mica 3) Electrolytic 4) paper 506. A capacitor may be used 1) to reduce the ripple 2) to store the charge 3) to filter the frequency signal 4) all of the above 507. In one time constant, capacitor takes the charge up to ___ % of its full charge 1) 63.2 2) 36.7 3) 20.6 4) 80.2 508. How many time constants needed by capacitor to changed upto 99.8% requires 1) 06 2) 04 3) 07 4) 03 509. The working voltage of capacitor depends on 1) type of dielectric 2) thickness of dielectric 3) frequency of voltage 4) all of the above 510.
In the above figure, value of resistance across AB is
1) 2) 3) 4)
1 2 5 4
ohm ohms ohms ohms
511. Relation of actual power, reactive power and apparent power should be 1) app. Power2 = real power 2 + reactive power 2 2) app. Power = real power + reactive power 3) app. Power = real power – reactive power 4) app. Power = real power x reactive power 512. Power factor is the ratio of _____ to _____ 1) actual power, apparent power 2) resistance, impedance 3) both (1) and (2) are correct 4) reactive power, apparent power 513. The scale of _______ meter is linear and even 1) D’Arsonval meter movement 2) Dynamometer ammeter 3) Moving iron is mount as voltmeter 4) Energy meter 514. The adverse effect of armature reaction is minimized by 1) shifting the brushes 2) placing the inter poles 3) placing the compoles 4) all of the above 515. The effect of current in armature causes 1) reduction in effective field strength 2) distortion in field flux
3) sparks between commutator and brushes 4) all of the above 516. Which of the following is incorrect 1) in 3 phase synchronous motor, field is rotating 2) in 3 phase induction motor, field is stationary and pulsating 3) synchronous motor is inherently not self starting 4) synchronous motor can be made self starting 517. Coercivity means ability 1) to annul the residual magnetism 2) to magnetise the core up to point of saturation 3) to restore magnetism 4) both (2) and (3) 518. Induction type instruments are used to measure 1) ac current 2) ac voltage 3) ac power 4) all of the above 519. When load on induction motor is decreased 1) speed increases 2) slip decreases 3) relative speed decreases 4) all of the above 520. Indication of battery Ni / Cad fully charged is given by 1) excessive formation of gases 2) significant change in sp-gravity 3) significant change in OCV 4) reduction in electrolyte level
