The $r.m.s.$ voltage of the wave form shown is

What is the $r.m.s$. value of an alternating current which when passed through a resistor produces heat which is thrice of that produced by a direct current of $2$ amperes in the same resistor......$amp$

The $r.m.s.$ value of potential difference $V$ shown in the figure is 

What is the maximum voltage of $220\, V$ ? 

If instantaneous current is given by $i = 4\cos \,(\omega \,t + \phi )$ amperes, then the $r.m.s$. value of current is

A current in circuit is given by $i = 3 + 4\, sin\, \omega t$. Then the effective value of current is