Question

When three identical bulbs are connected in series, the consumed power is 10W. If they are now connected in parallel then the consumed power will be :

• A. 30 W
• B. 90 W
• C. $\frac{10}{3}$ W
• D. 120 W

Answer 1

The correct option is B 90 W

In series, equivalent power $P_S=P/n=10$ or $P=10n=10\times 3=30W$ where P is the power of each bulb.
In parallel, equivalent power $P_P=nP=3\times 30=90W$