The magnitude of an $AC$ voltage used in other countries like America $(USA)$ is $.........$ and its frequency is $.......$.

Draw magnetic field lines produced around a current-carrying straight conductor passing through a cardboard. How will the strength of the magnetic field change when the point where the magnetic field is to be determined is moved away from the straight wire carrying a constant current? Justify your answer.

The strength of the induced potential difference depends on the relative speed between the coil and the magnet.

If you strike a sharp edge of a metallic knife against the north pole of a bar magnet,it will induce a north pole.

$(a)$ Describe an experiment with a diagram to show that force is exerted on a current-carrying conductor when placed perpendicular in a magnetic field.
$(b)$ How will this force change if the current in the conductor is increased?
$(c)$ Name a device that uses the above principle.

State Faraday's second law of electromagnetic induction.