The graph between the current in a purely resistive a.c circuit and the alternating voltage applied is a .

If the input voltage $V_{\mathrm{i}}$ to the circuit below is given by $V_{\mathrm{i}}\left(t\right)=A\cos \left(2\pi ft\right)\text{,}$ the output voltage is given by $V_{\mathrm{o}}\left(t\right)=B\cos \left(2\pi ft+\varphi \right)$.

Which one of the following four graphs best depict the variation of $\varphi$ vs $f$?

The phaser diagram of the alternating voltage across an unknown device $\mathrm{X}$ and current flowing through it are shown below.

Draw the graphical variation of current and voltage with $\mathrm{\omega t}$ through this device.

An alternating voltage is given by $E=100\sin \left(\omega t+\frac{\pi }{6}\right) \mathrm{V}$. The voltage will be maximum for the first time when time is ($T=$ time period)

In the circuit shown below, if $V_s=V_m\sin \omega t$ and the diode is ideal, the average value of voltage across $R_L$ is (Assume source resistance is zero)