Question

For a given voltage V, if resistance is changed from R to $\left(\frac{R}{n}\right)$, power consumed changes from P to

• A. nP
• B. $\frac{P}{n}$
• C. $n^{2}P$
• D. $\frac{P}{n^2}$

Answer 1

The correct option is A nP

Power consumed $P=\frac{V^2}{R}$ where $V=$ constant

New resistance $R^{\prime }=\frac{R}{n}$

$\therefore$ Power consumed by new resistance $P^{\prime }=\frac{V^2}{\frac{R}{n}}=nP$