# Electric Current – Old Year Questions

1. A 100-watt electric bulb is used for 10 hours. What will be the cost of electricity consumed, if the consumption cost is Rs. 5 per unit?

(a) Rs. 5
(b) Rs. 10
(c) Rs. 25
(d) Rs. 50

[R.A.S./R.T.S.(Pre) 2012]

2. If a bulb of 100 watt burns for 10 hours, the expenditure of electricity will be –

(a) 0-1 unit
(b) 1 unit
(c) 10 units
(d) 100 units

[41st B.P.S.C. (Pre) 1996]

3. Five bulbs each of 100-watt capacity in a tunnel are illuminated continuously for twenty hours. The consumption of electricity will be:

(a) One unit
(b) Two units
(c) Ten units
(d) Twenty units

[U.P.P.C.S. (Pre) 2017]

4. The value of 1 kilowatt hour is –

(a) 3.6 × 106J
(b) 3.6 × 103J
(c) 103 J
(d) 105J

[U.P.P.C.S. (Pre) 2006]

5. An electric bulb of 100 watts is used for 4 hours. The unit of electric energy used is-

(a) 400
(b) 25
(c) 4
(d) 0.4

[U.P. Lower Sub. (Pre) 2009]

6. Electricity consumption bill is based on the measurement of –
1. Watt
2. Voltage

3. Ohm
4. Ampere

(a) Only 1
(b) 1 and 2
(c) 2 and 3
(d) 1 and 4

[40th B.P.S.C. (Pre) 1995]

7. How many units of electricity will be consumed if you use a 60-watt electric bulb for 5 hours every day for 30 days?

(a) 12
(b) 9
(c) 6
(d) 3

[R.A.S./R.T.S. (Pre) 2003]

8. An electric bulb is connected to a 220 v generator. The current is 0.5 A. The power of the bulb is

(a) 110 w
(b) 110 v
(c) 440 w
(d) 220 w
(e) None of these

[Chhattisgarh P.C.S. (Pre) 2016]

9. The total resistance of a circuit having two parallel resistors is 1.403 kilo-ohm. If one of the resistors is 2.0 kilo-ohm, then the other resistor will be

(a) 1.403 kilo-ohm
(b) 2.0 kilo-ohm
(c) 3.403 kilo-ohm
(d) 4.70 kilo-ohm
(e) None of the above/More than one of the above

[66th B.P.S.C. (Pre) 2020]

10. Of the two bulbs in a house, one glows brighter than the other. In this context which of the following statements is correct?

(a) The brightness does not depend on the resistance.
(b) Both the bulbs have same the resistance.
(c) The bright bulb has larger resistance.
(d) The dim bulb has a larger resistance.

[U.P. Lower Sub. (Pre) 2008, U.P.P.C.S. (Pre) 2009]

11. Of the two bulbs in a house, one glows brighter than the other. Which of the two has a larger resistance?

(a) The dim bulb
(b) The brighter bulb
(c) Both have the same resistance
(d) The brightness does not depend on the resistance

[U.P.P.C.S. (Mains) 2013]

12. How two identical bulbs should be connected to get maximum light?

1. Both are connected in series.
2. Both are connected in parallel.

Select the correct answer using the code given below :

Code :

(a) In case 1 more
(b) In case 2 more
(c) Same in both 1 and 2
(d) Nothing can be said

[U.P. R.O./A.R.O. (Pre) 2021]

13. A dynamo which is said to generate electricity actually acts as a :

(a) Source of ions
(b) Source of electric charge
(c) Converter of energy
(d) Source of electrons

[U.P.P.C.S. (Mains) 2009]

14. ‘Dynamo’ is a device, which converts :

(a) Chemical energy into electrical energy
(b) Electrical energy into mechanical energy
(c) Mechanical energy into electrical energy
(d) Electrical energy into chemical energy

[U.P. P.C.S. (Pre) 2016, 39th B.P.S.C. (Pre) 1994, U.P.P.C.S. ( Pre) 1993, U.P.P.C.S. ( Pre) 1992]

15. Dynamo is a machine which is used for –

(a) Conversion of high voltage to low voltage
(b) Conversion of electrical energy to mechanical energy
(c) Conversion of mechanical energy to electrical energy
(d) Conversion of low voltage to high voltage

[U.P.P.C.S. (Mains) 2012, R.A.S./R.T.S.(Pre) 2012]

16. Turbines and Dynamos are used to convert which energy to electrical energy?

(a) Chemical energy
(b) Solar energy
(c) Mechanical energy
(d) Magnetic energy

[44th B.P.S.C. (Pre) 2000]

17. When electrical energy is converted into motion

(a) There is no heat loss
(b) Heat loss is 50 percent
(c) Heat loss is 30 percent
(d) Heat loss is 80 percent

[47th B.P.S.C. (Pre) 2005]

18. A device which converts electrical energy into mechanical energy is –

(a) Dynamo
(b) Transformer
(c) Electric motor
(d) Inductor

[U.P.P.C.S. (Mains) 2007, Uttarakhand P.C.S. (Pre) 2005]

19. In electrical motor :

(a) heat is converted into electrical energy
(b) electrical energy is converted into heat
(c) electrical energy is converted into mechanical energy
(d) mechanical energy is converted into electrical energy
(e) None of the above / More than one of the above

[64th B.P.S.C. (Pre) 2018]

20. The device which works on the principle of electromagnetic induction is

(a) Ammeter
(b) Voltmeter
(c) Dynamo
(d) Electric motor

[U.P. R.O./A.R.O. (Pre) 2017]

21. A device which converts chemical energy into electrical energy is called –

(a) Battery
(b) Motor
(c) Generator
(d) Moving coil meter

[R.A.S./R.T.S. (Pre) 2013]

22. Electric motors operating at low voltages tend to burn out because –

(a) They draw more current which is inversely proportional to the voltage.
(b) They draw more current which is inversely proportional to the square root of the voltage.
(c) They draw heat proportional to v2
(d) Low voltage sets in electrical discharge.

[U.P.P.C.S. (Pre) 2008]

(a) depends on the amount of the electrolyte
(b) depends on the current passed in the electrolyte
(c) depends on the volume of the solvent in which the electrolyte is dissolved
(d) is a universal constant
(e) None of the above / More than one of the above

[66th B.P.S.C. (Pre) 2020]

24. Consider the following statements regarding a motor car battery –

1. The voltage is usually 12 V.
2. The electrolyte used is hydrochloric acid.
3. Electrodes are lead and copper.
4. Capacity is expressed in ampere-hour.

Which of the above statements is correct?

(a) 1 and 2
(b) 2 and 3
(c) 3 and 4
(d) 1 and 4

[I.A.S. (Pre) 1999]

25. Nickel-Cadmium (Ni-Cd) battery is used in :

(a) Calculator
(b) Cordless electronic appliances
(c) Transistors
(d) All of the above

[Uttarakhand P.C.S. (Pre) 2016]

26. Which of the following metals is used as filament in lighting bulbs?

(a) Iron
(b) Molybdenum
(c) Silver
(d) Tungsten

[44th B.P.S.C. (Pre) 2000]

27. The filament of an electric bulb is made of –

(a) Magnesium
(b) Iron
(c) Nichrome
(d) Tungsten

[U.P.P.C.S (Pre) 2011, U.P.P.C.S. (Pre) 2005, U.P.P.C.S. (Pre) 1990]

28. The filament of an electric bulb is made of :

(a) Tungsten
(b) Nichrome
(d) Aluminium

[Uttarakhand P.C.S. (Pre) 2012]

29. Consider the following statements : An ordinary light bulb has a rather short life because the:

1. Filament wire is not uniform.
2. Bulb cannot be evacuated completely.
3. Wires supporting the filament melt at high temperatures.

Which of the above statements is correct?

(a) 1 and 3
(b) 2 and 3
(c) 1 and 2
(d) 1, 2 and 3

[I.A.S. (Pre) 1999]

30. The temperature of the filament of lighted electric bulb is generally :

(a) 100oC to 500oC
(b) 1000oC to 1500oC
(c) 2000oC to 2500oC
(d) 3000oC to 3500oC

[R.A.S./R.T.S.(Pre) 2007]

31. Lightning can even burn a tree because it contains tremendous amount of

(a) Heat energy
(b) Electric energy
(c) Chemical energy
(d) Nuclear energy

[M.P.P.C.S. (Pre) 2017]

32. Consider the following statements :

Assertion (A): Lightning conductors prevent buildings from damages in the event of lightning strike.
Reason (R): The electric charge conduct to ground through the wire, instead of passing through the structure.

Select the correct answer using the codes given below:

Code :

(a) Both (A) and (R) are correct, and (R) is the correct explanation of (A).
(b) Both (A) and (R) are correct, but (R) is not the correct explanation of (A).
(c) (A) is correct but (R) is wrong.
(d) (A) is correct but (R) is wrong.

[Uttarakhand P.C.S.(Mains) 2002, U.P.P.C.S. (Pre) 1999]

33. In a three-pin electrical plug longest pin should be connected to

(a) Ground terminal
(b) Live terminal
(c) Neutral terminal
(d) Any terminal

[U.P.P.C.S. (Pre) 2007]

34. In electric apparatus ‘earth’ is used:

(a) To reduce the expenditure
(b) Because the apparatus used 3-phase
(c) For safety
(d) In the form of fuse

[U.P.P.C.S. (Pre) 2002]

35. The electric current does not flow between two properly connected charged bodies if they are having

(a) Same charge
(b) Same capacity
(c) Same resistivity
(d) Same potential

[U.P.P.S.C. (R.I.) 2014]

36. A fuse is used in main electric supply as a safety device. Which one of the following statements about the fuse is correct?

(a) It is connected in parallel with the main switch
(b) It is made mainly from silver alloys
(c) It must have a low melting point
(d) It must have a very high resistance

[I.A.S. (Pre) 1998]

37. The principle of fuse is

(a) Chemical effect of electricity
(b) Mechanical effect of electricity
(c) Heating effect of electricity
(d) Magnetic effects of electricity

[43rd B.P.S.C. (Pre) 1999]

38. A fuse wire is characterized by:

(a) Low resistance and high melting point.
(b) Low resistance and low melting point.
(c) High resistance and low melting point.
(d) High resistance and high melting point.

[U.P. P.C.S. (Pre) 1993]

39. Fuse wire used for safety of household have :

(a) Low melting point
(b) High melting point
(c) High resistance
(d) Low resistance.

[R.A.S./R.T.S. (Pre) 1997-98]

40. The filament of a halogen lamp is an alloy of –

(a) Tungsten and iodine
(b) Tungsten and bromine
(c) Tungsten and sodium
(d) Molybdenum and sodium

[R.A.S./R.T.S.(Pre) 1999]

41. Assertion (A): The temperature of a metal wire rises when an electric current is passed through it.
Reason (R): Collision of metal atoms with each other releases heat energy.

Code :

(a) Both (A) and (R) are true and (R) is the correct explanation of (A)
(b) Both (A) and (R) are true but (R) is not a correct explanation of (A)
(c) (A) is true but (R) is false
(d) (A) is false but (R) is true

[I.A.S. (Pre) 1998]

42. Domestic electrical wiring is basically a :

(a) Series connection
(b) Parallel connection
(c) Combination of series and parallel connections
(d) Series connection within each room and parallel connection elsewhere

[I.A.S. (Pre) 1996]

43. A wire with black insulation during electric supply is–

(a) Live wire
(b) Earth wire
(c) Neutral wire
(d) Fuse wire
(e) None of the above

[Chhattisgarh P.C.S. (Pre) 2014]

44. What is the order of magnitude of electric resistance of the human body (dry)?

(a) 102 ohm
(b) 104 ohm
(c) 106 ohm
(d) 108 ohm

[I.A.S. (Pre) 2005]

45. Full form of C.F.L. is –

(a) Compact Fluorescent Lamp
(b) Centrally Fixed Lamp
(c) Chemical Fluorescent Lamp
(d) Condensed Fluorescent Lamp

[U.P.P.C.S. (Mains) 2015]

46. Light Emitting Diode (LED) work on principle of :

(a) Laser
(b) Thermionic emission
(c) Photoelectric code
(d) Electroluminescence

[Jharkhand P.C.S. (Pre) 2021]

47. Assertion (A): Light Emitting Diode (LED) lamps offer longer service life as compared to Compact Fluorescent Lamps (CFL).
Reason (R): Light Light-emitting diode (LED) lamps are more energy efficient as compared to Compact Fluorescent Lamps (CFL).

Select the correct answer using the codes given below:

(a) Both (A) and (R) are true, and (R) explains (A).
(b) Both (A) and (R) are true, but (R) does not explains (A).
(c) (A) is true, and (R) is false.
(d) (A) is false, and (R) is true.

[R.A.S./R.T.S.(Pre) 2013]

48. What is the difference between a CFL and an LED Lamp?

1. To produce light, a CFL uses mercury vapour and phosphor while an LED lamp uses semi-conductor material.
2. The average life span of a CFL is much longer than of an LED lamp.
3. A CFL is less energy-efficient as compared to an LED lamp.

Which of the statements given above is/are correct?

(a) 1 only
(b) 2 and 3
(c) 1 and 3
(d) 1, 2 and 3

[I.A.S. (Pre) 2011]

49. With reference to street lighting, how do sodium lamps differ from LED lamps?

1. Sodium lamps produce light in 360 degrees but it is not so in the case of LED lamps.
2. As street lights, sodium lamps have a longer life span than LED lamps.
3. The spectrum of visible light from sodium lamps is almost monochromatic while LED lamps offer significant colour advantages in street lighting.

Select the correct answer using the code given below.

(a) 3 only
(b) 2 only
(c) 1 and 3 only
(d) 1, 2 and 3

[I.A.S. (Pre) 2021]

50. What gases are filled in fluorescent tube?

(a) Neon
(b) Sodium
(c) Mercury
(d) Mercury and neon

[U.P. P.C.S. (Pre) 1990]

51. In comparison to an electric bulb, a fluorescent tube is preferred because –

(a) It has greater external outer surface to radiate/emit the light.
(b) There is no efect of voltage fuctuation on it.
(c) In the tube, electric energy almost converted into light energy.
(d) None of these.

[U.P. P.C.S. (Pre) 2009]

52. How does the white light produce in the tube?

(a) by heating up the copper wire
(b) by heating up the filament
(c) by accelerating the atoms
(d) by oscillating the molecules

[47th B.P.S.C. (Pre) 2005]

53. What is the gas inside an electric bulb?

(a) Oxygen
(b) Air
(c) Carbon dioxide
(d) None of the above

[M.P.P.C.S. (Pre) 2000]

54. Fluorescent tubes are filled with a choke. The choke coil-

(a) Steps up the line voltage
(b) Steps down the line voltage
(c) Reduces current in the circuit
(d) Chokes low-frequency current

[I.A.S. (Pre) 2000]

55. With reference to the electric potential which of the following statements is/are correct?

1. It is a scalar quantity.
2. It is a vector quantity.

Select the correct answer using the codes given below.

Codes :

(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

[U.P. P.C.S. (Pre) 2021]

56. If potential difference and current flowing through a wire is increased twice each then electric power :

(a) Will remain unaffected
(b) Will increase four times
(c) Will increase two times
(d) Will decrease by half
(e) None of these

[Chhattisgarh P.C.S. (Pre) 2015]

57. Two wires have their lengths, diameters and resistivity all in the ratio of 1: 2. If the resistance of the thinner wire is 10 ohm, the resistance of the thicker wire is :

(a) 5 ohm
(b) 10 ohm
(c) 20 ohm
(d) 40 ohm

[I.A.S. (Pre) 2001]

58. Small drops of the same size are charged to V volts each. If n such drops coalesce to form a single large drop, its potential will be :

(a) n2/3 V
(b) n1/3 V
(c) n V
(d) N–1 V

[U.P. Lower Sub. (Mains) 2015]

59. Given below are two statements, one labelled as Assertion (A) and the other labelled as Reason (R).

Assertion (A): Transformer is useful for stepping up or stepping down voltages.
Reason (R): Transformer is a device used in D.C. circuits.

In the context of the above two statements, which one of the following is correct?

(a) Both (A) and (R) are true and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true but (R) is not a correct explanation of (A).
(c) (A) is true but (R) is false
(d) (A) is false but (R) is true

[I.A.S. (Pre) 1996]

60. The transformer is used for

(a) Converting AC into DC
(b) Converting DC into AC
(c) To step-up DC voltages
(d) To step-up or step-down AC voltages

[U.P.P.C.S. (Pre) 2006]

61. Which of the following is the purpose for which a transformer is used?

(a) To convert AC into DC
(b) To convert DC into AC
(c) To step-up or step-down AC voltage
(d) To step up DC voltage

[U.P.P.C.S. (Mains) 2011]

62. A mobile phone charger is –

(a) An inverter
(b) A UPS
(c) A step up transformer
(d) A step down transformer

[U.P.P.C.S. (Pre) 2017]

63. Some pairs of devices and associated energy changes are given below :

(i) Electric generator – Mechanical to electrical
(ii) Electric motor – Electrical to mechanical
(iii) Diesel engine – Light to electrical
(iv) Solar cell – Chemical to mechanical

Which of the above pair/s is/are correctly matched?

(a) (i) and (ii)
(b) (i) and (iii)
(c) (ii) and (iv)
(d) (iii) and (iv)

[R.A.S./R.T.S.(Pre) 2013]

64. The basic difference between an AC generator and a DC generator is that –

(a) An AC generator has an electromagnet while a DC generator has a permanent magnet
(b) The AC generator has slip rings while the DC generator has a commutator
(c) DC generator will generate a higher voltage
(d) AC generator will generate a higher voltage

[Chhattisgarh P.C.S. (Pre) 2018]

65. Alternate current is not preferable –

(a) To charge storage battery
(b) To run/start a electric motor
(c) To transmit electric power
(d) To heat up electric toaster

[R.A.S./R.T.S. (Pre) 1994]

66. The device used for converting alternating current to direct current is called –

(a) Inverter
(b) Rectifier
(c) Transformer
(d) Transmitter

Chhattisgarh P.C.S. (Pre) 2008, U.P.P.C.S. (Pre) 2006

67. Alternating current is converted to direct current –

(a) By Dynamo
(b) By Motor
(c) By Transformer
(d) By Rectifier

[U.P. U.D.A./L.D.A. (Spl) (Mains) 2010]

68. Assertion (A): In India, electricity distribution companies calculate the consumption of electricity in kWh.
Reason (R): The electrical system in India works at a frequency of 60 Hz.

Code :

(a) both (A) and (R) are individually true, and (R) is the correct explanation of (A).
(b) both (A) are (R) are individually true, but (R) is not a correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.

[M.P.P.C.S. (Pre) 2008]

69. Which of the following options represents the consumption of power in ascending order–

(a) Television, fan, electronic press, electronic kettle
(b) Television, fan, electronic kettle, electronic press
(c) Fan, television, electronic press, electronic kettle
(d) Electronic press, electronic kettle, fan, television

[U.P.P.C.S. (Pre) 1992]

70. The earth’s magnetic field is due to

(a) Currents circulating inside the core
(b) Presence of a huge magnet at is centre
(c) Moving charges in space outside
(d) None of the above

[U.P.P.C.S. (Mains) 2011]

71. What is the source of electrical energy in an artificial satellite ?

(a) Solar cells
(b) Mini nuclear reactor
(c) Dynamo
(d) Thermopile

[U.P.P.C.S. (Pre) 2014, 2006, 2000, M.P.P.C.S. (Pre) 2000]

72. Consider the following statements :

Assertion (A) :Space-based solar power (SBSP), it is suggested be made a national goal.
Reason (R) :Supply of SBSP is 99% uninterrupted throughout the year, besides the enormity of energy availability.

Select the correct answer using the codes given below :

Code :

(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.

[U.P.P.C.S. (Pre) 2010]

73. With reference to technologies for solar power production, consider the following statements :

1. ‘Photovoltaics’ is a technology that generates electricity by direct conversion of light into electricity, while ‘Solar Thermal’ is a technology that utilizes the Sun’s rays to generate heat which is further used in electricity generation process.
2. Photovoltaics generates Alternating Current (AC), while Solar Thermal generates Direct Current (DC).
3. India has manufacturing base for Solar Thermal Technology, but not for Photovoltaics.

Which of the statements given above is/are correct?

(a) 1 only
(b) 2 and 3 only
(c) 1, 2 and 3
(d) None

[I.A.S. (Pre) 2014]

74. With reference to solar water pumps, consider the following statements:

1. Solar power can be used for running surface pumps and not for submersible pumps.
2. Solar power can be used for running centrifugal pumps and not the ones with piston.

Which of the statement given above is/are correct?

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

[I.A.S. (Pre) 2020]

75. Which one of the following elements is used in solar cells?

(a) Silicon
(b) Cerium
(c) Astatine

[Uttarakhand P.C.S. (Pre) 2012]

76. Photovoltaic cells are :

(a) Solar cells
(b) Thermal cells
(c) Sulphur cells
(d) Molar cells

[U.P. P.C.S. (Pre) 2016]

77. Photovoltaic cells are related to :

(a) Nuclear Energy
(b) Geo Thermal Energy
(c) Solar Energy
(d) Wind Energy

[R.A.S./R.T.S. (Pre) 2016]