Inside a solenoid,the magnetic field is constant in magnitude and direction.

$(a)$ Name the type of electric current generated by most of the power stations in our country.
$(b)$ Why is it preferred over the other type?
$(c)$ State the frequency of the power supply generated in India.

Mention the shape of the magnetic field lines around a current-carrying straight conductor.

What does the divergence of magnetic field lines near the ends of a current-carrying straight solenoid indicate?

How can you magnetise a piece of magnetic material?

Explain briefly different methods of producing induced electromotive force $(emf)$.