Question

In the circuit shown, the inductor and capacitor are ideal and source has no internal resistance. The circuit is in resonance.

• A. If a dielectric slab is inserted in the capacitor, current will now lag behind the applied voltage.
• B. If an iron rod is inserted in the inductor, current will now lead the applied voltage.
• C. If an iron rod is inserted in the inductor, current will now lag behind the applied voltage.
• D. If a dielectric slab is inserted in the capacitor, current will now lead the applied voltage.

Answer 1

Answer: (A), (C)

The correct options are
A If a dielectric slab is inserted in the capacitor, current will now lag behind the applied voltage.
C If an iron rod is inserted in the inductor, current will now lag behind the applied voltage.


$\tan \varphi =\frac{\omega L-\frac{1}{\omega C}}{R}$
(A) $C\uparrow \Rightarrow \omega L>\frac{1}{\omega C}\Rightarrow$ inductive
(B) $L\uparrow \Rightarrow \omega L>\frac{1}{\omega C}\Rightarrow$ inductive