Equivalent Resistance Multiple Choice Questions [MCQ] – Series and Parallel Circuits

Multiple choice questions on Equivalent resistance in circuits.

Equivalent Resistance Circuit 1

Find the equivalent resistance at points ab:

1. 2.5 ohms
2. 5 ohms
3. 7.5 ohms
4. 10 ohms

Correct answer: 3. 7.5 ohms

Solution: Req = 5 ohm + (5 ohms || 5 ohms)

= 5 ohms + (1/{(1/5) + (1/5)})

= 5 + 2.5 = 7.5 ohms

Also see: Series and Parallel Resistors MCQ

Equivalent Resistance Circuit 2

The equivalent resistance Req in the circuit given below is:

1. 10 ohms
2. 20 ohms
3. 30 ohms
4. 40 ohms

Correct answer: 3. 30 ohms

Solution:

R₂ || R₃ = 1/(1/R₂ + 1/R₃ ) = 1/(1/10 + 1/10) = 5 ohms

Now

R₁ + R₂ || R₃ + R₄ = 5 + 5 + 20 = 30 ohms

Given below are a few tips for solving resistors in parallel: