Question

The resistance of a wire is 10 ohm if its length is incresed by 10%by stretching

Answer 1

The resistance of a wire is 10 ohm. It`s length is increased by 10% by stretching. The new resistance will be(1)12ohm (2) 1.2ohm (3)1.3ohm (4)1.1ohm

As Resistance is directly proportional to the length of the resistance wire,

R = kl^2

After length gets increased by 10% we get,

R’ = k(l + 0.l)^2

divide both we get,

R/R’ = 1/(1.1)^2 => 1/1.21

R’ = 1.21 R ohm

2option is correct

Answer 2

Let new R = y

Let the original length = x

New length is 10% increased

=> x + $\frac{10x}{100}$

=> x + $\frac{x}{10}$

=> $\frac{10x}{10}$ + $\frac{x}{10}$

=> $\frac{11x}{10}$

Please check the attachment for full solution

:)