Question

the length of a wire is doubled . by what factor does the resistance change


I think so ans is 2 times bcoz
R proposotional to L/A
if 2L=2R
say me is it correct or not​

Answer 1

Answer:

4 times

Explanation:

Let,

Length = l,

area of cross section =A,

resistivity= p

then,

resistance R=pL/A

Now as the length is doubled. But the volume of the wire will remain same.

so, new area of cross section = l * A/2l

= A/2

therefore new resistance will be,

R' = p*2l/(A/2)

= 4pl/A

=4 R

Resistance will be 4 times of the previous resistance after it is stretched to double of its length.

Result:

Resistance will be 4 times of the previous resistance.