$A$ constant current flows in a horizontal wire in the plane of the paper from east to west as shown in the figure. The direction of the magnetic field at a point will be North to South:

Why does a magnetic needle deflect when brought close to a current carrying conductor? Explain the rule to find the direction of force on a current carrying conductor.

Give the factors on which the magnetic field produced by a current-carrying solenoid depends.

On which principle does an electric motor work?

$(a)$ State the function of a fuse in an electric circuit. How is it connected in the domestic circuit?
$(b)$ An electric fuse of rating $3 \, A$ is connected in a circuit in which an electric iron of power $1.5 \, kW$ is connected,which operates at $220 \, V$. What would happen? Explain.

$(a)$ $A$ coil of insulated copper wire is connected to a galvanometer. What will happen if a bar magnet is:
$(i)$ pushed into the coil with its north pole entering first?
$(ii)$ withdrawn from inside the coil?
$(iii)$ held stationary inside the coil?
$(b)$ Name the above phenomenon and mention the name of the scientist who discovered it. State the law that relates the direction of current in the coil with the direction of motion of the magnet.