Question

A length of wire having resistance 10 ohm is drawn out , so that its length is increased by 50%. Calculate the resistance of the wire in its new shape and size.​

Answer 1

The resistance of a wire can be expressed as R=AρLwhere,

ρ is the resistivity of the wire

L is the length of the wire

A is the area of cross section of the wire

In this case, the wire is stretched so as to increase its length by 20% i.e. factor of 1.2. 

Here, the wire's cross-sectional area(CSA) reduces by factor of 1.2 times of its original value as volume of wire is constant.

A1L1=A2L2

A2=1.2A1

R2=A2ρL2=1.2A1ρ1.2L1

R2=1.44A1ρL1=1.44×10=14.4Ω

Hence, the new resistance is 14.4 ohms

hope it helps you

MARK AS BRAINLIST PLS I NEED IT