Question

If a wire of resistance "R" is stretched 'n' times its new resistance is "R1" . If it is compressed 'n' times its new resistance is "R2". Find the ration R2/R1.​

Answer 1

Explanation:

Correct option is

C

4 : 1

As we know that, R

1

=ρ

a

l

=ρ

V

l

2

,

where l= length of wire, a= area of cross-section of the wire and V= volume of the wire.

So, R

1

∝l

2

⇒

R

2

R

1

=(

l

2

l

1

)

2

=(

2

1

)

2

⇒R

2

:R

1

=4:1

Hope it is helpful