Q. 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 :
A) f/4
B) 8f
C) f/(2√2)
D) 2f
Explanation
[Solution from source] The resonant frequency is f = 1/(2π√(LC)). Replacing L by 2L and C by 4C multiplies LC by 8, so the frequency becomes f/√8 = f/(2√2). The frequency decreases; it does not increase to 8f. Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.