For a series LCR circuit inductive reactance $X_L$ is equal to resistance $R$ and also equal to twice the capacitive reactance $X_C$. The impedance of the circuit and the phase difference between voltage V and current i are respectively

An alternating voltage $e = 150\sqrt{2}\sin 100t$ volt is applied to a capacitor of capacity $2\ \mu\text{F}$. The root mean square value of current in the circuit is

In an LCR circuit at resonance, the a.c. source current is
A) maximum in a series LCR circuit only.
B) maximum in a parallel LCR circuit only.
C) maximum in both series and parallel LCR circuits.
D) minimum in both series and parallel LCR circuits.
The correct answer is

A glass slab of thickness $6.0$ cm is placed on the piece of paper on which an inkdot is marked. By how much distance would an inkdot appear to be raised? The velocity of light in glass is $2 \times 10^8 \text{ ms}^{-1}$ and that in air is $3 \times 10^8 \text{ ms}^{-1}$.