A wire of a certain material is stretched slowly by ten percent. Its new resistance and specific resistance become respectively.

Options

A. both remain the same
B. `1.1` times, `1.1` times
C. `1.2` times, `1.1` times
D. `1.21` times, same

Answer

D

Explanation

`l A = l(1 + 10//100) A' rArr A' = A//1.1`
`(R')/(R) = (rho l'//A')/(rho l//A) = (1.1 l//(A//1.1))/(l//A) = 1.21`
`R' = 1.21 R`
Specific resistance depends on temperature and material, hence remains same.