Question

Each resistor consumes 100 W when connected across 230 V supply. If two such resistors are connected in series across the 230 V supply, the power consumed by the two together is

1. 200 W
2. 25 W
3. 50 W
4. 100 W

Answer 1

Correct Answer - Option 3 : 50 W

Power consumed by each resistor, \(P = \frac{{{V^2}}}{R}\)

\(\begin{array}{l} \Rightarrow 100 = \frac{{{{230}^2}}}{R}\\ \Rightarrow R = 529\;{\rm{\Omega }} \end{array}\)

Two resistors connected in series, \({R_{new}} = 1058\;{\rm{\Omega }}\)

Power consumed, \({P_{new}} = \frac{{{V^2}}}{{{R_{new}}}} = \frac{{{{230}^2}}}{{1058}} = 50\;Wa\)