A resistor with R = 300 and an inductor are connected in series across an ac sou
ID: 1633263 • Letter: A
Question
A resistor with R = 300 and an inductor are connected in series across an ac source that has voltage amplitude 500 V. The rate at which electrical energy is dissipated in the resistor is 286 W. What is the impedance Z of the circuit? (Points : 20)
300
362
512
262
724
which answer is correct ? and why
A resistor with R = 300 and an inductor are connected in series across an ac source that has voltage amplitude 500 V. The rate at which electrical energy is dissipated in the resistor is 286 W. What is the impedance Z of the circuit? (Points : 20)
Explanation / Answer
The average power dissplated by the resistor is, P=Irms^2 R Irms=V rms/Z Pavg=(V rms/Z)^2 R V rms=Vmax/sqrt 2 Z=Vsqrt R/2P =500 sqrt 300/2(286) =262 ohm.