Question

If length of the conductor of resistance 1 ohm is stretched to thrice of its initial length, then find the new resistance of the conductor.​

Answer 1

Explanation:

9ohm

resistance is directly proportional to square if length (coz area remains constant here)

Answer 2

9 ohm

The stretching of wire is constant since the volume is constant.

L=Length of the wire

A=area of the wire

R=resistance

R = ρ L A

A1×L1=A2×L2

L2=3L1

A2=A1÷3

R  ′  =  ρ×3L÷(A/3)

R  ′  =9×R

A resistance R wire is stretched until it reaches n times its initial length.   The area of cross section goes from A to A times n when the length is extended n times to n times length.