Question

Which of the following combinations of length(l) and diameter(d) of cross-section of a wire will give us minimum resistance?

• A. l and d
• B. l/2 and 2d
• C. 2l and d
• D. 2l and d/2

Answer 1

The correct option is B

l/2 and 2d

Resistance of the conductor depends (i) on its length, (ii) on its area of cross-section. $R=\rho \frac{l}{A}$ where 'l' is the length and 'A' is the area of cross- section.