How can it be shown that a magnetic field exists around a wire through which a direct current is passing?

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

$(a)$ 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.

What is meant by electromagnetic induction? State the rule which helps in determining the direction of induced current.

State the energy change which takes place when a magnet is moved inside a coil having a galvanometer at its ends. Name this phenomenon.

By placing an iron-like metal inside the solenoid,its magnetic field becomes $......$