What is a solenoid? Draw the pattern of magnetic field lines of a solenoid through which a steady current flows.

What is short-circuiting in an electric supply?

On which principle does an electric bell work?

The magnetic field around a current-carrying straight conductor is:

$(a)$ What is the direction of magnetic field lines inside a bar magnet and outside of it?
$(b)$ What does the degree of closeness of the field lines represent?

Two coils $C_{1}$ and $C_{2}$ are wrapped around a non-conducting cylinder. Coil $C_{1}$ is connected to a battery and a key $K$,and coil $C_{2}$ is connected to a galvanometer $G$. On pressing the key $K$,current starts flowing in the coil $C_{1}$. State your observations in the galvanometer for the following cases:
$(i)$ When key $K$ is pressed on.
$(ii)$ When current in the coil $C_{1}$ is switched off.
$(iii)$ When the current is passed continuously through coil $C_{1}$.
$(iv)$ Name and state the phenomenon responsible for the above observation. Write the name of the rule that is used to determine the direction of the induced current.