Q. When the length and area of cross-section both are doubled, then its resistance
A) Will become half
B) Will be doubled
C) Will remain the same
D) Will become four times
Explanation
(c) $R_{1} \propto \frac{l}{A} \Rightarrow R_{2} \propto \frac{2l}{2A}i.e.R_{2} \propto \frac{l}{A}$
$\therefore R_{1} = R_{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.