If an $AC$ main supply is given to be $220 \ V$,what would be the average e.m.f. during a positive half cycle?

An alternating current is given by $I=100 \sin (50 \pi t)$. How many times will the current become zero in one second (in $times$)?

The peak value of an alternating current is $5 \text{ A}$ and frequency is $60 \text{ Hz}$. How long will the current,starting from zero,take to reach the peak value?

$A$ $40 \ \Omega$ electric heater is connected to a $200 \ V, 50 \ Hz$ mains supply. The peak value of electric current flowing in the circuit is approximately......$A$

An electric current has both $DC$ and $AC$ components. The $DC$ component is $8 \ A$ and the $AC$ component is given as $I = 6 \sin \omega t$. The $rms$ value of the resultant current is . . . . . . (in $A$)

An alternating current at any instant is given by $i = [6 + \sqrt{56} \sin (100 \pi t + \frac{\pi}{3})] \ A$. The rms value of the current is . . . . . . . (in $A$)