- #1
Vibhor
- 971
- 40
Homework Statement
Q. What will happen when
a) A bulb rated 240 V 100W is connected to a 120 V supply .
b) A bulb rated 120 V 100W is connected to a 240 V supply
Homework Equations
P = V2/R
The Attempt at a Solution
a) R = 2402/100 = 576Ω
Power dissipated when the bulb is put across a 120V supply = 1202/576 = 25W .
The bulb lights dimmer .
b) R = 1202/100 = 144Ω
Power dissipated when the bulb is put across a 240V supply = 2402/144 = 400W .
Since power dissipated is more than the rated power ,the bulb fuses .
Is this reasoning correct ?
Many thanks !