There are n identical electric bulbs. Each bulb is designed to draw power P when connected independently across the mains voltage. The n bulbs are now connected in series across the same mains supply. The total power drawn is:
Options

Question

There are n identical electric bulbs. Each bulb is designed to draw power P when connected independently across the mains voltage. The n bulbs are now connected in series across the same mains supply. The total power drawn is:

Options

G1 Physics · Accepted Answer

Let the resistance of each bulb be R and the mains RMS voltage be V. When one bulb is connected independently, P = V²/R. When n identical bulbs are connected in series, R e q R_eq R e ​ q = nR. Therefore total power is P t o t a l P_total P t ​ o t a l = V²/(nR) = (1/n)(V²/R) = P/n. Correct option: B.