Question

The resistance of a wire of 0.01 cm radius is 10 Ω. If the resistivity of the wire is 50 × 10^-8 Ω, find the length of this wire.

Answer 1

Given, Radius, r = 0.01 cm = 0.0001 m

Resistance, R = 10 Ω

Resistivity, `rho = 50 xx 10^-8` Ω m

R = `rho "L"/"A"`

L = `"RA"/rho`

`= (10 xx 3.14 xx (0.0001)^2)/(50 xx 10^-8)`

= 0.628 m

Hence, the length of the wire is 0.628 m.