A light bulb is connected to a 240 V wall socket. The current in the bulb depends on the time t according to the relation I = (0.707 A) sin[ (251.2 Hz) t ].
(a) What is the frequency of the alternating current?
Hz
(b) What is the resistance of the bulb's filament?
(c) What is the average power delivered to the light bulb?
W
Physics? Alternating Current?
(a)f=251.2/2pi=40 Hz
(b)R=240/0.707*o.707=480 Ohms
(c)P=240*240/480=120 watts
Reply:(a) we have 2*pi*f=251.2 Hz.
f= 251.2/2*3.14
f= 39.96 hz
(b) from the eqn, max current= 0.707.
therefore, mean current= max current/sqrt2
therefore, mean current is o.5 amper
(c) power= V*I
=240* 0.5
=120 watt
ta daa...
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