An electric bulb rated for 200w and 100v is connected to a circuit having a 200v supply. What is the resistance R that must be put in series with the bulb so that the bulb draws 200w?

Asked by saradamahapatra9999 | 7th Mar, 2019, 10:29: AM

Expert Answer:

Rated power of the bulb is 200 W and operating voltage is 100 V.
Current drawn by the bulb = power/voltage = 200/100 = 2 A
Resistance = Voltage/current = 100/2 = 50 Ω
when this bulb is connected in 200 V supply, we need to ensure the current passing through this bulb is 2 A
by connecting additional resistance.
total resistance required to get 2 A from 200 V supply = 200/2 = 100 Ω
Since resistance of bulb is 50 Ω , we need to add additional 50 Ω resistance in series.

Answered by Thiyagarajan K | 7th Mar, 2019, 11:36: AM

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