The frequency of $AC$ mains in India is ....... $Hz$.

An alternating voltage is represented as $E = 20 \sin 300t$. The average value of voltage over one cycle will be ....... $V$.

Two sinusoidal voltages of the same frequency are shown in the diagram. What is the frequency and the phase relationship between the voltages? (Frequency in $Hz$ $\to$ Phase lead of $N$ over $M$ in radian)

The heat produced in a resistor by an $AC$ current is three times the heat produced by a $2 \, A$ $DC$ current. What is the $rms$ value of the $AC$ current in $A$?

What is $rms$ (root mean square) value? Write the formula of $rms$ current for an alternating current.

An alternating e.m.f. is given by $e = e_{0} \sin(\omega t)$. In what time will the e.m.f. reach half its maximum value,if $e$ starts from zero? ($T$ = Time period)