Question

a wire of resistance 100 ohm and length l is increased to twice it's original length.Calculate its new resistance.​

Answer 1

Answer:

Explanation:

When l is made twice, area of cross section gets halved. Therefore new resistance would be

R=rho*2l/a/2

R=rho*4l/a

R=4(rho*l/a)

R=4(100)

R=400 ohms