Ohm's Law — Homi Bhabha Exam Physics MCQs with Solutions
Free Homi Bhabha Exam Physics Ohm's Law MCQs with step-by-step solutions (5 questions). Part of Electricity & Magnetism. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Ohm's Law · medium · theory
Ohm's law states that, at constant temperature, the current through a conductor is:
A. independent of the potential difference
B. inversely proportional to the potential difference
C. proportional to the square of the voltage
D. directly proportional to the potential difference across it ✓ Correct
Solution: $V = IR$, so $I \propto V$ at constant temperature and resistance.
Q2 — Ohm's Law · medium · numerical
A potential difference of 12 V is applied across a 4 Ω resistor. The current through it is:
A. 48 A
B. 0.33 A
C. 3 A ✓ Correct
D. 16 A
Solution: $I = \dfrac{V}{R} = \dfrac{12}{4} = 3$ A.
Q3 — Ohm's Law · medium · numerical
A current of 2 A flows through a resistor when 10 V is applied across it. Its resistance is:
A. 5 Ω ✓ Correct
B. 12 Ω
C. 0.2 Ω
D. 20 Ω
Solution: $R = \dfrac{V}{I} = \dfrac{10}{2} = 5$ Ω.
Q4 — Ohm's Law · hard · numerical
A current of 0.5 A flows through a 20 Ω resistor. The potential difference across it is:
A. 10 V ✓ Correct
B. 20.5 V
C. 0.025 V
D. 40 V
Solution: $V = IR = 0.5 \times 20 = 10$ V.
Q5 — Ohm's Law · hard · theory
On a graph of potential difference (V) against current (I) for an ohmic conductor, the slope of the straight line gives the:
A. current
B. resistance ✓ Correct
C. charge
D. power
Solution: Since $V = IR$, the V–I graph is a straight line whose slope equals the resistance R.