A piece of copper is to be shaped into a conducting wire of maximum resistance. The suitable length and diameter are ………… and ………… respectively.

Options

A. L and d
B. 2 L and `d//2`
C. `L//2` and 2 d
D. 2 L and d

Answer

B

Explanation

Resistance, `R= (rhoL)/(A)= (4phoL)/(piD^(2))`
:. Option (b) is suitable among the four options.