Question

2. A wire of length 1 and resistance R is stretched to get
the radius of cross-section halved What is the new
resistance of the wire after stretching?
in wires?​

Answer 1

Length (l) is doubled & Area of cross section (A) is halved.

l becomes 2l & A becomes

2

A

R=P

A

L

now take l=2l,A=

2

A

R=

A/2

P2l

=4P

A

L

⇒4R

Resistance becomes 4 times

1) Resistivity does not depend on its length 02 Area.

Hence, it does not change.