Electro Magnetic Induction And Alternating Currents Question 221
Question: A transistor-oscillator using a resonant circuit with an inductor L (of negligible resistance) and a capacitor C in series produce oscillations of frequency f. If L is doubled and C is changed to 4C, the frequency will be
Options:
A) $ 8f $
B) $ f/2\sqrt{2} $
C) $ f/2 $
D) $ f/4 $
Show Answer
Answer:
Correct Answer: B
Solution:
- We know that frequency of electrical oscillation in L.C. circuit is
$ f=\frac{1}{2\pi }\sqrt{\frac{1}{LC}} $
Now, L=2L & C=4C $ f’=\frac{1}{2\pi }\sqrt{\frac{1}{2L\cdot 4C}}=\frac{1}{2\pi }\sqrt{\frac{1}{LC}}\times \frac{1}{2\sqrt{2}}\Rightarrow ,f’ $
$ =\frac{1}{2\sqrt{2}}\times f $
