$A$ current-carrying solenoid behaves like a bar magnet.

How can you magnetise a piece of magnetic material?

Whose magnetic field is like a magnetic field of a bar magnet?

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.

$(i)$ $A$ compass needle gets deflected when brought near a current-carrying conductor. Why?
$(ii)$ What happens to the deflection of the needle when the current in the conductor is increased?

Which of the following statements is incorrect for a current-carrying solenoid?