Electric Current and Ohm’s Law Questions with Answers

Electric Current and Ohm’s Law questions with answers are among the most common electronics aptitude questions in GATE, SSC JE, and RRB JE exams. This topic explains the fundamental relationship between voltage, current, and resistance — the backbone of electrical circuit analysis. Understanding Ohm’s Law and its applications helps solve both theoretical and numerical questions efficiently. Here, you’ll find well-explained problems covering resistivity, conductance, and real-world circuit examples to improve your technical proficiency.

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The unit of electric current is

A A) Volt
B B) Watt
C C) Ampere
D D) Ohm

Answer: Option C

Explanation: Electric current is measured in amperes (A), which represents the rate of flow of electric charge.

Ohm's Law defines the relationship between

A A) Voltage, Current, and Power
B B) Current, Voltage, and Resistance
C C) Resistance, Inductance, and Capacitance
D D) Charge, Energy, and Power

Answer: Option B

Explanation: Ohm's Law states that voltage across a conductor is directly proportional to the current through it, with resistance being the constant of proportionality (V = IR).

The SI unit of resistance is

A A) Ampere
B B) Volt
C C) Ohm
D D) Coulomb

Answer: Option C

Explanation: Resistance is measured in ohms (Ω), named after the German physicist Georg Simon Ohm.

If resistance increases, for a constant voltage, current will

A A) Increase
B B) Decrease
C C) Remain same
D D) Become zero

Answer: Option B

Explanation: According to Ohm's Law (I = V/R), current is inversely proportional to resistance when voltage is constant.

The potential difference is measured in

A A) Watt
B B) Ohm
C C) Volt
D D) Ampere

Answer: Option C

Explanation: Potential difference, also known as voltage, is measured in volts (V) and represents electrical pressure or electromotive force.

A conductor has resistance 10 Ω and current 2 A flows through it. The potential difference is

A A) 5 V
B B) 10 V
C C) 20 V
D D) 2 V

Answer: Option C

Explanation: Using Ohm's Law: V = I × R = 2 A × 10 Ω = 20 V.

Which of the following is a good conductor?

A A) Glass
B B) Silver
C C) Rubber
D D) Wood

Answer: Option B

Explanation: Silver is one of the best electrical conductors among common materials due to its very low resistivity.

The instrument used to measure current is

A A) Voltmeter
B B) Ammeter
C C) Galvanometer
D D) Wattmeter

Answer: Option B

Explanation: An ammeter is specifically designed to measure electric current and is always connected in series with the circuit.

The instrument used to measure voltage is

A A) Voltmeter
B B) Ammeter
C C) Rheostat
D D) Multimeter

Answer: Option A

Explanation: A voltmeter is used to measure potential difference (voltage) and is always connected in parallel across the component.

Q10

Resistance of a conductor depends on

A A) Length and area
B B) Color
C C) Shape only
D D) Temperature only

Answer: Option A

Explanation: Resistance depends on the material's properties (resistivity), length, and cross-sectional area (R = ρL/A).

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Electric Current and Ohm's Law Questions and Answers

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Electric Current and Ohm's Law Questions and Answers

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