Question

A (100 W, 200 V) bulb is connected to a 160 volts supply. The power consumption would be

• A. 100 W
• B. 125 W
• C. 64 W
• D. 80 W

Answer 1

Answer: (C)

64 W

Answer 2

Given ,
For bulb,
Power , $P = 100 \,W$ , $V = 200\, V$
As we know ,
$P = V^2/R$,
$R = V^2/P$
$=200?200/100$
$= 400 \,\Omega$
So, For $160 \,V$ supply ,
as $V = I\, R$
So, $I = 160400=0.4 \,A$
Power Consumption ,
$P = V\, I$
$= 160 ?0.4$
$= 64 \,W$