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Objective Questions:
1. In our houses we receive AC electric power of .........with a frequency of .........
2. The frequency for A.C. (alternating current) in USA is ..........

3. The main advantage of A.C power transmission over D.C power transmission
over’ long distance is
(a) AC transmit without much loss of energy
(b) less insulation problem
(c) less problem of instability
(d) easy transformation.

4. If the current values periodically from zero to a maximum value, back to zero and
then reverses its direction, the current is
(a) direct
(b) alternative
(c) pulsating
(d) none of the above

Subjective Questions:

1. .An alternating electric current has a frequency of 50 Hz. How many times does
it change its direction in one second? Give reason for your answer.

2. Write one difference between direct current and alternating current. Which one of
the two is mostly produced at power stations in our country? Name one device
which provides alternating current. State one important advantage of using
alternating current.

3. (a) Mention the colour code used for live, neutral and earth wire.
(b) You want to connect a 2 kW electric oven in the electric circuit. In which
power line would you connect it and why? What may happen if you connect it
wrongly in the other power line?
4. State one main difference between ac and dc. Why ac is preferred over dc for
long range transmission of electric power? Name one source each of dc and
ac.