Question

(a) What do you understand by the terms 'direct current' and 'alternating current'?
(b) Name some sources of direct current and some of alternating current.
(c) State an important advantage of alternating current over direct current.
(d) What is the frequency of A.C. supply in India?

Answer 1

(a) If current flows in one direction only, it is called direct current, e.g., current generated by battery.
If current reverses its direction after fixed intervals of time, it is called alternating current, e.g., current supplied at homes.

(b) Some sources of direct current are dry cells, battery, car battery and D.C. generators.
Some sources of alternating current are A.C. generators, power stations.
(c) An important advantage of alternating current over direct current is that alternating current can be transmitted to long distances without much loss of electric energy.

(d) The frequency of A.C. supply in India is 50 Hz.