Electro Magnetic Induction And Alternating Currents Question 74
Question: In a circuit $ L,,C\text{ and }R $ are connected in series with an alternating voltage source of frequency $ f $ . The current leads the voltage by 45°. The value of $ C $ is [CBSE PMT 2005]
Options:
A) $ \frac{1}{2\pi f(2\pi fL+R)} $
B) $ \frac{1}{\pi f(2\pi fL+R)} $
C) $ \frac{1}{2\pi f(2\pi fL-R)} $
D) $ \frac{1}{\pi f(2\pi fL-R)} $
Show Answer
Answer:
Correct Answer: A
Solution:
$ \tan \varphi =\frac{X_{C}-X_{L}}{R} $
Þ $ \tan 45^{o}=\frac{\frac{1}{2\pi fC}-2\pi fL}{R} $
Þ $ C=\frac{1}{2\pi ,f(2\pi fL+R)} $
