In: Physics
An ac signal at a certain frequency is applied across a 40-mH inductor and a 100-Ω resistor. If the power factor of this circuit is 0.40, what is the value of the frequency?
A.160 Hz B.600 Hz C.910 Hz D.410 Hz C.200 Hz
A circuit consists of inductor, resistor and an ac signal generator.
The power factor of the LR circuit is,
Here R is the resistance and Z is the impedance of the circuit.
Rearrange the equation for Z.
The impedance of the circuit is,
The reactance of the inductor is,
Rearrange the equation for frequency f.
Therefore, the frequnecy is 910 Hz. Option (c) is the correct asnwer.