KCET2026PhysicsAlternating Current
A light bulb rated 100 W is connected to an AC source of 220 V, 50 Hz. The rms current through the bulb is
Options
- A0.454 A
- B0.545 A
- C2.20 A
- D0.22 A
Correct answer
A. 0.454 A
Step-by-step solution
The power of the light bulb is given as P = 100 W. The rms voltage of the AC source is V_ rms = 220 V. For a purely resistive load like a light bulb, the power factor is 1 . The average power is given by the relation: P = V_ rms I_ rms Rearranging the formula to solve for the rms current I_ rms : I_ rms = P V_ rms Substituting the given values: I_ rms = 100 220 I_ rms = 5 11 0.454 A Answer: 0.454 A