Question

200W and 100W bulbs both meant for operation at 220v are connected in series.when connected to a 220 v supply the power consumed by them will be

Answer 1

200W and 100W bulbs both meant for operation at 220v are connected in series.when connected to a 220 v supply the power consumed by them will be

solution : resistance of first bulb, R1 = V²/P1 = (220)²/200 = 48400/200 = 242 Ω

resistance of 2nd bulb, R2 = V²/P2 = (220)²/100 = 48400/100 = 484 Ω

now both the bulbs are connected in series combination,

so, Req = R1 + R2 = 242 + 484 = 726 Ω

now, current through bulb, i = V/Req

= 220/726 ≈ 0.303A

so, power consumed by them = i²Req

= (0.303A)² × 726 Ω

≈ 66.65 W

hence power consumed by bulbs will be 66.65W

Answer 2

Answer:

66 W

Explanation:

P2=V2/R2

R2=220 SQUARE/P SQUARE

=220 X 220/200

=242

R2= V2/RESISTOR =220 SQUARE / 726

=66 W