The current in the primary circuit of a potentiometer is `0.2 A`. The specific resistance and cross-section of the potentiometer wire are `4xx10^(-7)` ohm meter and `8xx10^(-7)m^(2)` respectively. The potential gradient will be equal to -

Options

A. 1V/m
B. 0.5V/m
C. 0.1V/m
D. 0.2V/m

Answer

C

Explanation

Let l be the length of potentiometer wire. Resistance of the potentiometer wire can be written as follows:
`R = rho (l)/(A) = (4 xx 10^(-7)) (l)/((8 xx 10^(-7))) = (l)/(2)` Potential difference across the length of potentiometer wrie
`V=I R rArr V= (0.2) (1//2)`
Potential gradient `V//l = 0.1 V//m`
Hence, option (c) is correct