Electro Magnetic Induction And Alternating Currents Question 155
Question: The power factor in a circuit connected to an A.C. The value of power factor is
Options:
A) unity when the circuit contains an ideal inductance only
B) unity when the circuit contains an ideal resistance only
C) zero when the circuit contains an ideal resistance only
D) unity when the circuit contains an ideal capacitance only
Show Answer
Answer:
Correct Answer: B
Solution:
- $ \cos ,\phi =\frac{R}{Z} $ ,
where Z is the impedance & $ Z=\sqrt{R^{2}+{{(X_{L}-X_{C})}^{2}}} $ ,
if there is only resistance then
$ Z=R\Rightarrow \cos ,\phi =1 $
