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

Which type of magnet is used in a crane to lift cars?

Identify the type of magnetic fields represented by the magnetic field lines given below and name the type of conductors which can produce them.

The magnetic field produced by a straight current-carrying conductor is in the form of concentric circles.

In the arrangement shown in the figure,there are two coils wound on a non-conducting cylindrical rod. Initially,the key is not inserted. Then the key is inserted and later removed. Then

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