What is the average power dissipation in an ideal capacitor in an $AC$ circuit?

$A$ coil has an inductance of $2 \ H$. The ratio of its reactance,when it is connected first to an $AC$ source and then to a $DC$ source,is

$L$, $C$ and $R$ are connected in series to an $A.C.$ source. Which one of the following is true? Phase relation between current and voltage is such that

The inductive reactance of a coil is $R \ \Omega$. If the inductance of the coil is tripled and the frequency of the $A.C.$ supply is also tripled,then the new inductive reactance will be:

When an $a.c.$ source is connected across a pure capacitor, the correct phase relation between current and $emf$ is:

If the current through an inductor of inductance $L$ is given by $I = I_0 \sin(\omega t)$,then the voltage across the inductor will be