Resistors in Series and Parallel MCQs

Q1. Two resistors of 6 Ω and 6 Ω are connected in parallel. What is their equivalent resistance Rp?

• A.3 Ω
• B.12 Ω
• C.6 Ω
• D.36 Ω

Answer: A. 3 Ω

Given 6 Ω, asked for What is their equivalent resistance Rp?. By For resistors in parallel, 1/Rp = 1/R1 + 1/R2 = 1/6 + 1/6 = 2/6 = 1/3, so Rp = 3 Ω. For resistors in parallel, 1/Rp = 1/R1 + 1/R2 = 1/6 + 1/6 = 2/6 = 1/3, so Rp = 3 Ω. Shortcut: for two equal resistors R in parallel, the result is R/2. Thus option A) 3 Ω. Others fail: option B) '12 Ω' doesn't hold - 12 Ω is the series total (6 + 6), not the parallel value; option C) '6 Ω' is incorrect: Two equal 6 Ω resistors in parallel give half, i.e. 3 Ω, not 6 Ω.

Q2. Two resistors of 4 Ω and 6 Ω are connected in series. What is the equivalent resistance of the combination?

• A.10 Ω
• B.2.4 Ω
• C.24 Ω
• D.2 Ω

Answer: A. 10 Ω

Q3. Four resistors, each of 12 Ω, are connected in series to form a closed square loop ABCD. What is the equivalent resistance between two adjacent corners A and B?

• A.9 Ω
• B.12 Ω
• C.48 Ω
• D.36 Ω

Answer: A. 9 Ω