Question

A potentiometer wire has a length of 4m and resistance of 5Ω. It is connected in series with 495 Ω resistance and a cell of e.m.f. 4V. The potential gradient along the wire is ______

Options

• 0.01 V/m

• 0.03 V/m

• 0.02 V/m

• 0.04 V/m

Answer 1

A potentiometer wire has a length of 4m and resistance of 5Ω. It is connected in series with 495 Ω resistance and a cell of e.m.f. 4V. The potential gradient along the wire is 0.01 V/m.

Explanation:

Total resistance = 495 + 5 = 500 Ω

current I = `4/500 = 8 xx 10^-3 A`

P.D. across the wire = IR

= `8 xx 10^-3 xx 5= 40 xx 10^-3  V`

∴ Potential gradient = `(40 xx 10^-3)/4`

= 10^-2 V/m = 0.01 V/m