The current in the primary circuit of a potentiometer is

Question:

The current in the primary circuit of a potentiometer is $0.2 \mathrm{~A}$. The specific resistance and crosssection of the potentiometer wire are $4 \times 10^{-7} \mathrm{ohm}$ metre and $8 \times 10^{-7} \mathrm{~m}^{2}$ respectively. The potential gradient will be equal to :-

1. $0.2 \mathrm{~V} / \mathrm{m}$

2.  $1 \mathrm{~V} / \mathrm{m}$

3. $0.5 \mathrm{~V} / \mathrm{m}$

4. $0.1 \mathrm{~V} / \mathrm{m}$

Correct Option: , 4

Solution: