Question

Find the change in value of current if the lenght of a conductor is doubled and the area of cross section is made one fourth of the original

Answer 1

Now, resistance=(rho×l)/A

if the length is doubled the length becomes 2l.

and if we make area of cross section 1/4 then it becomes A/4

now resistance would be

R' = (rho×2l)/A/4

= (8×rho×l)/A

so current will decrease

by eight times