KCET · Physics · Units and Dimensions
The average power dissipated in A.C. circuit is \( 2 \) watt. If a current flowing through a circuit is \( 2 \)
\( A \) and impedance is \( 1 \Omega \), what is the power factor of the \( A C \) circuit?
- A \( 0.5 \)
- B \( 11 \)
- C \( 00 \)
- D \( \frac{1}{\sqrt{2}} \)
Answer & Solution
Correct Answer
(A) \( 0.5 \)
Step-by-step Solution
Detailed explanation
Power of ac circuit is given as \(P=V I \cos \phi\)
Using Ohm's law, \(V=I R\)
\(P=I^{2} Z \cos \phi\)
Given, \(P=2 W ; I=2 A ; Z=1 \Omega\)
Substituting the values, we get
\(2 W=(2)^{2} \times 1 \times \cos \phi\)
\(\Rightarrow \cos \phi=\frac{2}{4}=\frac{1}{2}=0.5\)
Therefore, power factor of ac circuit is \(0.5\).
Using Ohm's law, \(V=I R\)
\(P=I^{2} Z \cos \phi\)
Given, \(P=2 W ; I=2 A ; Z=1 \Omega\)
Substituting the values, we get
\(2 W=(2)^{2} \times 1 \times \cos \phi\)
\(\Rightarrow \cos \phi=\frac{2}{4}=\frac{1}{2}=0.5\)
Therefore, power factor of ac circuit is \(0.5\).
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