When a $DC$ voltage of $200\, V$ is applied to a coil of self inductance $\frac{{2\sqrt 3 }}{\pi }\,H$, a current of $1\, A$ flows through it. But by replacing $DC$ source with $AC$ source of $200\, V$, the current in the coil is reduced to $0.5\, A$. Then, the frequency of $AC$ supply is......$Hz$

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 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......$amp$

An $AC$ source rated $220\, V , 50\, Hz$ is connected to a resistor. The time taken by the current to change from its maximum to the rms value is

In a certain circuit current changes with time according to $i = 2\sqrt t .$ r.m.s. value of current between $t = 2$ to $t = 4s$ will be