# Ohm’s Law MCQ [Quiz Questions with Answers]

Ohm’s law is one of the fundamental principles of Electrical Engineering. It relates the flow of electric current to the applied voltage. The law is applicable to resistive circuits. In this post you’ll learn the Basic Electrical Engineering MCQ on Ohm’s law.

**Statement: The electric current flowing through a constant resistor is directly proportional to the voltage applied across it**

*Mathematically: V ∝ I or V = IR*

where

V = Voltage (In volts)

I = Current (In amps)

R = Resistance (In ohms)

More about Electrical Units and Quantities

## Basic Ohm’s Law Solved MCQ Example

Solution: I = V/R = 10 V / 5 Ω = 2 A

## A 1 kΩ resistor has 20 mA of current flowing through it. Determine the value of the applied voltage

A 1 kΩ resistor has 20 mA of current flowing through it. Determine the value of the applied voltage:

- 0.05 V
- 1 V
- 15 V
- 20 V

Correct answer: 4. 20 V

## An electric lamp draws 2 A current when connected to a 120 V source. What is the resistance of source

An electric lamp draws 2 A current when connected to a 120 V source. What is the resistance of source:

- 2 Ω
- 60 Ω
- 120 Ω
- 240 Ω

Correct answer: 2. 60 Ω

**Explanation: R = V/I = 120 V/ 2A = 60 Ω**

## An electric heater having element resistance of 2 ohms will draw how much current when connected to a 230 V source

An electric heater having element resistance of 2 ohms will draw how much current when connected to a 230 V source:

- 2 A
- 75 A
- 115 A
- 230 A

Correct answer: 3. 115 A

Solution: I = V/R = 230 V / 2 ohms = 115 A

## The resistance of a certain conductor is 100 ohm and the current passing through it is 5 A. What is the value of potential difference acting across it

The resistance of a certain conductor is 100 ohm and the current passing through it is 5 A. What is the value of potential difference acting across it

- 500 V
- 20 V
- 10 V
- 15 V

Correct answer: 500 V

**From formula: V = IR = 5 A * 100 ohms = 500 V**

## Two series resistors of resistance 5 ohms and 15 ohms are connected in series. If the voltage drop across 5 ohm resistors is 2.5 V. Calculate current across 15 ohms resistor

Two series resistors of resistance 5 ohms and 15 ohms are connected in series. If the voltage drop across 5-ohm resistors is 2.5 V. Calculate current across 15 ohms resistor:

- 0.5 A
- 1 A
- 5 A
- Insufficient data

Correct answer: 1. 0.5 A

From Ohm’s law: I = V/R = 2.5/5 = 0.5 A

**Since both are in series, same current flows across them.**