Question

Four resistance 10$\Omega$, 5$\Omega$, 7$\Omega$ and 3$\Omega$ are connected so that they form the side of a rectangle AB, BC, CD and DA respectively. Another resistance of 10$\Omega$ is connected across the diagonal AC. The equivalent resistance between A and B is

• A. 2$\Omega$
• B. 5$\Omega$
• C. 7$\Omega$
• D. 10$\Omega$

Answer 1

Answer: (B)

5$\Omega$

The equivalent resistance across A and C is $R_{AC}=10||(3+7)=10||10=\frac{10\times 10}{10+10}=5\Omega$

Now The equivalent resistance between A and B is $R_{AB}=10||(5+5)=10||10=\frac{10\times 10}{10+10}=5\Omega$