Question

Two electric bulbs rated $P_1,W,V$ volt, $P_2,W,V$ volt are connected in parallel, across

V-volt supply. Total power consumed is:

• A. $\frac{P_1+P_2}{2}$
• B. $\sqrt{P_1.P_2}$
• C. $\frac{P_1.P_2}{P_1+P_2}$
• D. $P_1+P_2$

Answer 1

The correct option is D $P_1+P_2$

$P_1=\frac{V^2}{R_1},P_2=\frac{V^2}{R_2}$
When connected in parallel.
Total power $=\frac{V^2}{R_1}+\frac{V^2}{R_2}$ $=\frac{V^2}{\frac{V^2}{P_1}}+\frac{V^2}{\frac{V^2}{P_2}}$

$=P_1+P_2$