Q. A wire of a certain material is stretched slowly by ten percent. Its new resistance and specific resistance become respectively
A) Both remain the same
B) 1.1 times, 1.1 times
C) 1.2 times , 1.1 times
D) 1.21 times, same
Explanation
(d) In Stretching of wire $R \propto l^{2} \Rightarrow \frac{R_{1}}{R_{2}} = \left( \frac{l_{1}}{l_{2}} \right)^{2}$
If $l_{1} = 100$, then $l_{2} = 110\ \Rightarrow \frac{R_{1}}{R_{2}} = \left( \frac{100}{110} \right)^{2}$
$\Rightarrow R_{2} = 1.21\ R_{1}$
Resistivity doesn’t change with stretching
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.