Give the name of the physical quantity in an $LCR$ circuit that corresponds to mass $m$ in forced oscillations.

$L$,$C$,and $R$ denote inductance,capacitance,and resistance respectively. Pick out the combination which does not have the dimensions of frequency.

In the circuit shown in the figure,the $ac$ source gives a voltage $V = 20\cos(2000t)$. Neglecting source resistance,the voltmeter and ammeter readings will be:

Given below are two statements:
Statement-$I$: The reactance of an $ac$ circuit is zero. It is possible that the circuit contains a capacitor and an inductor.
Statement-$II$: In an $ac$ circuit, the average power delivered by the source never becomes zero.
In the light of the above statements, choose the correct answer from the options given below:

Mark the incorrect statement.

The following figure shows an $AC$ generator connected to a 'black box' through a pair of terminals. The box contains possible $R, L, C$ or their combination,whose elements and arrangements are not known to us. Measurements outside the box reveal that $e = 75 \sin(\omega t) \text{ V}$ and $i = 1.5 \sin(\omega t + 45^\circ) \text{ A}$. Then,the wrong statement is: