Out of the following bulb rated 40W, 220 V, 50 W, 220 V and 100 W, 220 V, which one will glow
brightest when connected in series to a supply of 220 v ?
Answers
Explanation:
Resistance of 100Wbulb=200
2
/100=400ohms
Resistance of 60Wbulb=200
2
/60=666.67ohms
Resistance of 40Wbulb=200
2
/40=1000ohms
Therefore, total resistance in series = (400+666.67+1000)=2066.67ohms
Current in the circuit =200/2066.67=0.0967A
Therefore, actual power consumed by “40W”bulb=0.0967
2
x1000=9.35W (much lesser than any of the original)
The 40W bulb will grow the brightest as the current is constant in all three and it has the maximum resistance. But it would consume much less than 40W as the bulbs are connected in series, and voltage would be divided across all three filaments depending upon resistances.
when bulbs are connected in series combination then lowest watt bulb glow more means 40w bulb glow more * and if bulbs are connected in parallel combination so more watt bulb glow more