What is the shape of the magnetic field lines around a circular current-carrying conductor?

An electric generator works on the principle of electromagnetic induction.

$(a)$ Explain the difference between direct current and alternating current. Write one important advantage of using alternating current.
$(b)$ An air conditioner of $2 \,kW$ is used in an electric circuit having a fuse of $10 \,A$ rating. If the potential difference of the supply is $220 \,V$,will the fuse be able to withstand the current when the air conditioner is switched on? Justify your answer.

Explain with the help of a labelled diagram the distribution of magnetic field due to a current through a circular loop. Why is it that if a current-carrying coil has $n$ turns,the field produced at any point is $n$ times as large as that produced by a single turn?

Explain why a fuse should be joined with the live wire and not with the neutral wire in a domestic circuit.

When a light,straight conducting wire is suspended perpendicular to a strong magnetic field and an electric current is passed through it,the magnetic force acting on it is proportional to which of the following?