Choose the correct option.
$A$ rectangular coil of copper wires is rotated in a magnetic field. The direction of the induced current changes once in each

$A$ compass needle is placed near a current-carrying wire. State your observation for the following cases and give the reason for the same in each case:
$(a)$ Magnitude of electric current in the wire is increased.
$(b)$ The compass needle is displaced away from the wire.

$A$ magnetic compass shows a deflection when placed near a current-carrying wire. How will the deflection of the compass be affected if the current in the wire is increased? Support your answer with a reason.

$AB$ is a current-carrying conductor in the plane of the paper as shown in the figure. What are the directions of the magnetic fields produced by it at points $P$ and $Q$? Given $r_1 > r_2$, where will the strength of the magnetic field be larger?

$(a)$ What is an electromagnet? What does it consist of?
$(b)$ Name one material in each case which is used to make a: $(i)$ permanent magnet $(ii)$ temporary magnet.
$(c)$ Describe an activity to show how you can make an electromagnet in your school laboratory.

How can you show that the magnetic field produced by a given electric current in a wire decreases as the distance from the wire increases?