Question

SI unit of potential gradient is ______________.

• A. $Vcm$
• B. $\frac{V}{c{m}^2}$
• C. $Vm$
• D. $\frac{V}{m}$

Answer 1

Answer: (D)

$\frac{V}{m}$

A potentiometer is a long wire of length 4 to 10 metres with uniform cross-section of same material throughout and considerable resistance.

The resistance is thus uniform throughout.

If a fixed voltage is applied across this device, the voltage gets divided equally within equal intervals of length.

Hence the voltage per unit length is constant

$V\propto L$

$\therefore V=KL$

$\therefore \frac{V}{L}=K$

$K$ is potential gradient.

SI unit of voltage is Volt V, of length is metre m, so that of K is V/m