Question

26. A piece of wire of resistance 20N is drawn out so that its length is increased to twice its
originálength. Calculate the resistance of the wire in the new situation.​

Answer 1

Answer:

When length of wire is doubled i.e. 2l

Also it's area of cross section becomes half i.e 2A

Resistance R=Aρl=20Ω

New Resistance ,

R′=A′ρl′

=Aρ(2l)×2

=4Aρl=4(Aρl)

=4×20

=80Ω