MCQ Questions Based on Electrical Power and Energy for Class 10 Science

MCQ Questions Based on Electrical Power and Energy for Class 10

Here we are providing MCQ questions for class 10 science based on electrical power and energy. These questions are prepared by expert. These MCQs will help you to understand the topic well.

Q.1. The resistance of a conductor is reduced to half its initial value. In doing so the heating effects in the conductor will become:
(A) half
(B) one-fourth
(C) four times
(D) double

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Answer: (D)

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Q.2. Heating effect of a current carrying conductor is due to :
(A) Loss of kinetic energy of moving atoms
(B) Loss of kinetic energy of moving electrons
(C) Attraction between electrons and atoms
(D) Repulsion between electrons and atoms

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Answer: (B)

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Q.3. Rate of heat generated by electric current in a resistive circuit is expressed in:
(A) IR
(B) IR²
(C) I²R
(D) IR

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Answer: (C)

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Q.4. How much electrical energy in kilowatt hour is consumed in operating ten, 50 watt bulbs for 10 hours per day in a month of 30 days?
(A) 15
(B) 150
(C) 1500
(D) 15000

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Answer: (B)

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Q.5. Two heater wires of equal length are first connected in series and then in parallel with a battery. The ratio of heat produced in the two cases is:
(A) 2 : 1
(B) 1 : 2
(C) 4 : 1
(D) 1 : 4

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Answer: (D)

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Q.6. Laws of heating are given by :
(A) Faraday
(B) Joule
(C) Ohm
(D) Maxwell

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Answer: (B)

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Q.7. An electric iron draws a current of 4A when connected to a 220 V mains. Its resistance must be:
(A) 40 ohm
(B) 55 ohm
(C) 100 ohm
(D) none of these

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Answer: (B)

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Q.8. The correct relation between heat produce (H) and electric current I flowing is :

(A) H α I
(B) H α 1/I
(C) H α I²
(D) H α 1/I²

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Answer: (C)

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Q.9. An electric bulb is rated 220 V and 100 W. When it is operated on 110 V, the power consumed will be:
(A) 100 W
(B) 75 W
(C) 50 W
(D) 25 W

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Answer: (D)

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Q.10. Melting point of fuse wire must be :
(A) Moderate
(B) High
(C) Low
(D) Infinite

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Answer: (C)

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Q.11. An electric iron is based upon the principle of :
(A) magnetic effect of current
(B) heating effect of current
(C) chemical effect of current
(D) none of these

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Answer: (B)

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Q.12. Fuse wire is made up of :
(A) Copper
(B) Aluminium
(C) Alnico
(D) Lead tin alloy

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Answer: (D)

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Q.13. Which of the following terms does not represent electrical power in a circuit ?
(A) I²R
(B) IR²
(C) VI
(D) V²/R

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Answer: (B)

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Q.14. A 2 KW boiler used for 1 hour everyday consumes the following electrical energy in thirty days :
(A) 60 units
(B) 120 units
(C) 15 units
(D) None of these

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Answer: (A)

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Q.15. Two heater wires of same length and material but of different thickness are connected in series across a power supply. Thus power dissipated :
(A) Will be same in both
(B) Will be more in thinner wire
(C) Will be more in thicker wire
(D) Cannot be predicted

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Answer: (B)

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Q.16. Alloys are usually used in electrical heating devices because :
(A) Resistivity of an alloy is generally higher than that of constituent elements
(B) Alloys do not oxidize readily at high temperature
(C) Both (A) and (B)
(D) Neither (A) nor (B)

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Answer: (C)

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Q.17. You are given a wire 1 m long. In which one of the following cases, the energy drawn from the battery will be the largest ? Assume that the internal resistance of the battery is zero.
(A) Full length of the wire connected across the battery
(B) Half length of the wire connected across the battery
(C) Wire cut into four equal parts and they are connected in parallel to each other across the battery
(D) Wire is cut into two equal parts and they are connected in parallel to each other across the battery

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Answer: (C)

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Q.18. The filament of an electric bulb is made of tungsten because :
(A) its resistance is negligible
(B) it is cheaper
(C) its melting point is high
(D) its filament is easily made

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Answer: (C)

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Q.19. Heating element of electric iron is made up of :
(A) Nichrome
(B) Tungsten
(C) Constantan
(D) None of these

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Answer: (A)

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