Draw a neat labelled diagram of AC generator.

A student performs an experiment to study the magnetic effect of current around a current-carrying straight conductor. He reports that:
(i) the direction of deflection of the North-pole of a compass needle kept at a given point near the conductor remains unaffected even when the terminals of the battery sending current in the wire are interchanged.
(ii) for a given battery, the degree of deflection of an N-pole decreases when the compass is kept at a point farther away from the conductor. Which of the above observations of the student is incorrect and why?

A current-carrying straight conductor is placed in the East-West direction. What will be the direction of the force experienced by this conductor due to earth’s magnetic field? How will this force get affected on:
(a) reversing the direction of flow of current?
(b) doubling the magnitude of current?

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

Name the type of current in two cases.

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

Identify any one source for each type of these currents.