Question

WHAT WILL BE THE PERCENTAGECHANGE IN THE RESISTANCE OF A WIRE IF IT IS STRETCHED TO THRICE OF ITS INITIAL LENGTH?

Answer 1

Answer:

if it is streched Thrice of its initial length then final length will be 9 times increased .

Explanation:

L1 = L

L2 = 3L

R1 = R

R2 = X

AREA CHANGED IS CONSTANT

L ×A = A2 × 3L

A2 = A/3.

So area changed is A/3.

R = ROW × L /A1. ⬅️ LET EQ1

R2 = ROW × 3L / A/3

R2 = 9 ( ROW × L / A1 )

= 9R. ⬅️FROM EQ1 .