Electro Magnetic Induction And Alternating Currents Question 110
Question: A lamp consumes only 50% of peak power in an a.c. circuit. What is the phase difference between the applied voltage and the circuit current [MP PMT 2004]
Options:
A) $ \frac{\pi }{6} $
B) $ \frac{\pi }{3} $
C) $ \frac{\pi }{4} $
D) $ \frac{\pi }{2} $
Show Answer
Answer:
Correct Answer: B
Solution:
$ P=\frac{1}{2}V_{o}i_{o}\cos \varphi \Rightarrow P=P_{Peak}.\cos \varphi $
$ \Rightarrow \frac{1}{2}(P_{peak})=P_{peak}\cos \varphi \Rightarrow \cos \varphi =\frac{1}{2}\Rightarrow \varphi =\frac{\pi }{3} $
