Q. Which of the following combinations should be selected for better tuning of an L-C-R circuit used for communication?
A) R = 20 Ω, L = 1.5 H, C = 35 μF
B) R = 25 Ω, L = 2.5 H, C = 45 μF
C) R = 15 Ω, L = 3.5 H, C = 30 μF
D) R = 25 Ω, L = 1.5 H, C = 45 μF
Explanation
[Solution] Sharpest tuning needs the highest quality factor $Q = \frac{1}{R}\sqrt{\frac{L}{C}}$; option (3) gives Q ≈ 22.8, the largest. Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.