A $110 \,V$ $d.c$. heater is used on an $a.c.$ source, such that the heat produced is same as it produces when connected to $110 \,V$ $dc$ in same time-intervals. What would be the $r.m.s.$ value of the alternating voltage is .......... $V$

The output sinusoidal current versus time curve of a rectifier is shown in the figure. The average value of output current in this case is

What are $DC$ signals and $AC$ signals ? Why do we preferred an $AC$ signal ?

Match the following

Currents                                     $r.m.s.$ values

(1)${x_0}\sin \omega \,t$                               (i)$ x_0$

(2)${x_0}\sin \omega \,t\cos \omega \,t$                  (ii)$\frac{{{x_0}}}{{\sqrt 2 }}$

(3)${x_0}\sin \omega \,t + {x_0}\cos \omega \,t$        (iii) $\frac{{{x_0}}}{{(2\sqrt 2 )}}$

What is $rms$ ? Write the formula of $rms $ for current ? 

In an $ac$ circuit $I = 100\, sin \,200$ $\pi t.$ The time required for the current to achieve its peak value will be