Heating Effects of Current — Homi Bhabha Exam Physics MCQs with Solutions
Free Homi Bhabha Exam Physics Heating Effects of Current MCQs with step-by-step solutions (4 questions). Part of Electricity & Magnetism. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Heating Effects of Current · medium · theory
The heat produced in a resistor carrying a current is given by Joule's law of heating:
A. $H = I^2 R$
B. $H = I R t$
C. $H = I^2 R t$ ✓ Correct
D. $H = \dfrac{I t}{R}$
Solution: Joule's law: $H = I^2 R t$ — heat depends on the square of the current.
Q2 — Heating Effects of Current · hard · numerical
An electric device draws a current of 0.5 A at 220 V. Its power consumption is:
A. 110 W ✓ Correct
B. 55 W
C. 220.5 W
D. 440 W
Solution: Power $= V \times I = 220 \times 0.5 = 110$ W.
Q3 — Heating Effects of Current · medium · theory
Which of the following appliances works mainly on the heating effect of electric current?
A. Loudspeaker
B. Electric bell
C. Electric iron ✓ Correct
D. Electric fan
Solution: An electric iron (like heaters and geysers) uses the heat produced when current passes through a resistance wire.
Q4 — Heating Effects of Current · hard · theory
An electric fuse protects a circuit because, when the current becomes too large, the fuse wire:
A. cools the circuit
B. stores the charge
C. melts and breaks the circuit ✓ Correct
D. increases the current
Solution: Excess current heats the low-melting fuse wire until it melts, breaking the circuit and preventing damage.