Question

A copper wire of resistance R is made in such a way that its area is increased times . Find the new resistance R

Answer 1

Hyyy


Resistance= Resistivity x length/area

When the wire is stretched to double the length , the area of cross section gets reduced to half.

So when

New Resistance = Resistivity x 2length/area/2


New resistance = (Resistivity x area/length)x4

i.e, New resistance = Resistance x 4

So when the wire is stretched, the resistance multiplies by four times.

Hope you understood.