A light bulb is rated as 100 W, 230 V and is connected to a 230 V ac source. The value of peak current is
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 0.61 A
The rated voltage of an ac supply (230 V) is its rms value, so the power gives the rms current first.
\( \displaystyle I_{\mathrm{rms}} = \frac{P}{V_{\mathrm{rms}}} = \frac{100\,\mathrm{W}}{230\,\mathrm{V}} = 0.435\,\mathrm{A} \)
The peak current is \( \sqrt{2} \) times the rms current.
\( \displaystyle I_0 = \sqrt{2}\,I_{\mathrm{rms}} = 1.414 \times 0.435\,\mathrm{A} = 0.615\,\mathrm{A} \approx 0.61\,\mathrm{A} \)