List a few merits of alternating current.

Answer the following:

What is the frequency of household alternating current $\left(\mathrm{AC}\right)$ in India?

You are given following current-time graphs from two different sources:

What is the frequency of current in case II in India?

You are given following current $\left(I\right)$ - time $\left(t\right)$graphs.

(a) Name the type of current in each case.

(b) Identify one source for each of the currents.