Sunday, March 4, 2012

Physics Magnetism/Circuits Problems?

The power supply in a laptop computer requires an effective voltage of 9.0 volts from a 120 V line.



(a) If the primary coil has 500 turns, how many does the secondary coil have?

(b) A 140 mA current is in the computer. What current (in mA) is in the primary circuit?





The rms current in an ac circuit with a resistance of 180 is 0.64 A.

(a) What is the average power consumed by this circuit?

(b) What is the maximum power consumed by this circuit?Physics Magnetism/Circuits Problems?
a) Np/Ns = Vp/Vs, assume Vp=120v, Ns=37.5

b)Np/Ns = Is/Ip, Ip = 10.5mA



a)avg P = (0.64 x 0.707)^2 x 180

b)max P= 0.64^2 x 180

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