Question

Two copper wires have equal length but the thickness of one is twice that of the other. If the resistance of the thin wire is 10 Omega, find the resistance of the thick wire.

Answer 1

2.5 ohm

Explanation:

We know that R=pl/A

Since the wires have equal length l is same for both and p is also same as the two wires are of the same material.

Therefore R1/R2= A2/A1

R1- resistance of thin wire

A1-area of thin wire

A2/A1=[r2/r1]^2

r2=2r1

Solving,

10/R2=[2r1/r1]^2

10/4=R2

2.5 ohm=R2