Question

A wire of resistance is 4 ohm is stretched to doubled its length find the new resistance

Answer 1

Hey.

Here is the answer.

As R = p L/A

or, 4 = p L/ A...........(1)

and since the wire is stretched to double

so, new length = 2 L

new Area = A/2 as wire is stretched so area will get reduced to half

So, new resistance R' = p (2L) / (A/2)

or, R' = p 4L/A = 4 p L / A

or, R' = 4×4 = 16 ohm ......{from (1)}

So, resistance will get 4times and will become 16 ohm.

Thanks.