The magneitc field produced at the center of a current carrying circular coil of radius r, is

The magnetic moment of a current carrying circular coil of radius r varies as

The ratio of magnetic field at the centre of a current carrying circular coil to its magnetic moment is 'r'. If the current and the radius both are doubled. The new ratio will become

How does the magnetic field at the centre of a current carrying circular coil change, when current is doubled and its radius is halved?

What will be magnetic field at centre of current carrying circular loop of radius R?

What will be magnetic field at centre of current carrying circular loop of radius R?

Is the magnetic field at the centre of the current carrying circular coil parallel to the plane of the coil?

The magnetic field due to a current carrying circular coil on the axis, at a large distance r from the centre of the coil, varies approximately as ..........