Question

An electric bulb rated 500w at 200v used in circuit having 400v supply. Calculate resistance must be put in series with the bulb so that the bulb deliver 500w

Answer 1

Done answer is 20ohm

Answer 2

Hi friend,

We know that

Power =V²/R

R= (100)²/500

R= 20ohm.

I= V/R

I= 100/20

I= 5A.

Resistance = 100/5

Resistance = 20 ohm.

Total resistance in series= R1+R2

Resistance = 40-20

Resistance = 20ohm.

Hope this helped you a little!!!!