Question

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 4 times

Answer 1

The correct option is C Will remain the same

Resistance of the wire $R=\rho \frac{L}{A}$

Given; $L^{\prime }=2L$ and $A^{\prime }=2A$

$\therefore$ New resistance $R^{\prime }=\frac{\rho L^{\prime }}{A^{\prime }}=\rho \frac{2L}{2A}=R$

Thus its resistance will remain the same.