What is the nature of the magnetic field lines passing through the center of a current-carrying circular loop?

$(a)$ What is electromagnetic induction?
$(b)$ In what way can the magnitude of the induced current be increased?

$(a)$ 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.

What happens to the deflection of the compass needle placed at a point near a current-carrying straight conductor:
$(a)$ If the current is increased?
$(b)$ If the direction of current in the conductor is changed (reversed)?
$(c)$ If the compass is moved away from the conductor?

For a current in a long straight solenoid,$N-$ and $S-$ poles are created at the two ends. Among the following statements,the incorrect statement is:

In which of the following cases will maximum electric current be induced in the loop?