Question

A copper wire has a diameter 0.5 mm and resistivity 1.6 10^-8

ohm m.

(i) What will be the length of this wire to make the resistance of 12 Ohm

(ii) How much will be the resistance of another copper wire of same length but half the

diameter?​

Answer 1

Hello Mate!!

Answer:-

Given,

diameter of copper wire = 0.5mm = 5 × 10-⁴ m

resistivity = 1.6 × 10^-8 ohm.m

resistance = 10 ohm

Length = ?

we know,

R = dL/A

where R , d , L and A are resistance , resistivity , length and cross section area.

10 = 1.6 × 10^-8 × L/(πr²)

L = 10 × 3.14 × (2.5 × 10^-4)² × 10^8/1.6

L = 10× 3.14 × 6.25/1.6

L = 122.656 m

Hope it helps!!❤