technical question, plz answer with explanation

Ques. An electric bulb is rated 220V and 100W.Wen it is operated on 110V,the power consumed will be? i)100W ii)75W iii)50W iv)25W

Arjun
14 मार्च
1481 दृश्य
3 उत्तर

Your Answer

AR

Ashly
12 जुलाई

Answer is option 4

Explaination:

Power

P=I*V

where I is the current, V is the voltage

But ohms law says:

I=V/R

where R is the resistance

so:

P=V^2/R

so we know that when operated at 220 volts, the power is 100w, so we can work out the resistance:

R=220^2/100

R= 484 ohms.

Now when operated at 110 volts:

P=V^2/R
=110^2/484
=25 Watts