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Question
A light bulb is rated 100W for 220 V AC supply of 50 Hz. Calculate
- resistance of the bulb.
- the rms current through the bulb
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Solution
Data: Power (Vrms irms) = 100 W, Vrms = 220 V, f = 50 Hz
a. The resistance of the bulb,
R = `"V"_"rms"/"i"_"rms" = 220/(100//220)` = (22)(22) = 484 Ω
b. The rms current through the bulb,
`"i"_"rms" = "power"/"V"_"rms" = 100/220 = 0.4545`A
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