Question

Using a long extension cord in which each conductor has a resistance of 8Ω, a bulb marked as '100 W, 200 V' is connected to a 220 V dc supply of negligible internal resistance as shown in the figure. The power delivered to the bulb is ______ W.

 

विकल्प

• 93.70

• 90.45

• 98.21

• 80.56

Answer 1

Using a long extension cord in which each conductor has a resistance of 8Ω, a bulb marked as '100 W, 200 V' is connected to a 220 V dc supply of negligible internal resistance as shown in the figure. The power delivered to the bulb is 93.70 W.

Explanation:

The circuit can be shown in the figure.

The bulb is marked 100 W, 220 V.

Hence, the resistance of the filament of the bulb.

R = `V^2/P = (220 xx 220)/100` = 484Ω

Current in the given circuit.

I = `220/(484 + 8 + 8)`

= 0.44 A

Power is delivered to the bulb.

`I^2R_{"bulb"} = (0.44)^2(484)`

= 93.7 W