A series resonant circuit is made by connecting an inductor of inductance and a…
PHYSICS · Multi-part · CBSE · Physics · Alternating Current · Alternating Current
Problem
A series resonant circuit is made by connecting an inductor of inductance L and a capacitor of capacitance C in series with a negligible resistance source.
Answer the following questions about this circuit:
(i) Write the mathematical expression for the resonant frequency of the circuit in terms of L and C. Specify the physical quantity represented by each symbol you use.
(ii) Using the expression obtained in part (i), explain qualitatively how the resonant frequency will change in each of the following separate cases:
(a) The inductance is doubled while the capacitance remains unchanged.
(b) The capacitance is reduced to one-half while the inductance remains unchanged.
(iii) A student claims that it is more convenient to vary the inductance rather than the capacitance when tuning a portable radio set to lower broadcast frequencies. State and explain two practical reasons why variable capacitors are usually preferred over variable inductors in such radio receivers.