Practicing Success

Target Exam

CUET

Subject

Physics

Chapter

Current Electricity

Question:

The resistance of a wire of uniform diameter d and length l is R.  The resistance of the another wire of the same material but diameter 2d and length 4l  will be

Options:

2R

R

R/2

R/4

Correct Answer:

R

Explanation:

$ R = \frac{\rho l}{A}$

$ \frac{R'}{R} = \frac{l'}{l} \frac{A}{A'} = 4\times \frac{1}{4} = 1$

$\Rightarrow R'= R$