Q. Forty electric bulbs are connected in series across a $220\ V$ supply. After one bulb is fused, the remaining 39 are connected again in series across the same supply. The illumination will be
A) More with 40 bulbs than with 39
B) More with 39 bulbs than with 40
C) Equal in both the cases
D) In the ratio of $49^{2}\ :39^{2}$
Explanation
(b) When 1 bulb fuses, the total resistance of the circuit decreases hence the current increases. Since $P = i^{2}R,$ therefore illumination increases
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.