Question

A wire has a resistance of 10 ohm what will be its resistance if it is stretched by one tenth of its original length

Answer 1

Let original length of wire be l. As it has been stretched by one tenth of its length the new length becomes l+l/10=11l/10

Now volume remains constant.

l*A=11/10l*new area of cross section

new area=10/11A

Substituting the values in equation R=p*(l/A)

we get the new resistance as 121/100 times of the old one.

So new resistance will be 1.21*10=12.1 ohm

Answer 2

Answer:

due to stretching increase in length cause decrease in area and vice versa.