An ac series circuit consists of a voltage source of frequency 60 Hz and voltage amplitude V, a 238-Ω resistor, and a capacitor of capacitance 1.8 μF. What must be the source voltage amplitude V for the average electrical power consumed in the resistor to be 954 W? There is no inductance in the circuit.

Question

akohl · Answer

any ideas?

radar · Answer

It is a series circuit, so current will be our reference.|dw:1430183683412:dw| Since we are given the power absorbed by the resistor (954 watts - 238 Ohm Resistor) Calculate the current required using P=I^2 R,  I got a current of 2.00 A.  we can now calculate the voltage across the resistor E=IR or 476 volts.  Now we will update or diagram.

radar · Answer

|dw:1430184093915:dw| Note that the voltage is lagging the current by 90 degrees.  Don't forget "ELI the ICE Man"   Current leads voltage for capacitors.