Question

A straight uniform wire of resistance 36 $\Omega$ is bent in the form of a semi-circular loop. The effective resistance between the ends of the diameter of the semi-circular loop is

• A. $56/9 \Omega$
• B. $36/7 \Omega$
• C. $99/7 \Omega$
• D. $77/9 \Omega$

Hint:

When a uniform wire of total resistance R is bent into a circle, the resistance between the ends of a diameter is R/4. The resistance between two points that divide the circumference into lengths $l_1$ and $l_2$ is equivalent to two resistors, $R_1 = R(l_1/L)$ and $R_2 = R(l_2/L)$, connected in parallel.

Answer 1

The Correct Option is D