A small coil of radius r is placed at the centre of another coaxial coil of radius `R(Rgtgtr)` find the coeffcient for this pair of coils.

A small coil of radius r is placed at the centre of a large coil of radius R , where R gtgt r . The two coils are coplanar. The mutual inductance between the coils is proportional to

A small coil of radius r is placed at the center of a large coil of radius R, where R>>r. The two coils are coplanar. The mutual inductance between the coils is proportional to

A coil of radius r is placed at the centre of R>>r and coils are in same plane.The coefficient of mutual inductance between the coil is

Field at the centre of a circular coil of radius r , through which a current I flows is

A small, flat coil of resitance r is placed at the centre of a large, closed coil of resistance R . The coils are coplanar. Their mutual inductance is M . Initially a constant current i was flowing in the inner coil. If this curent is suddenly swithced off, what charge will circulate in the outer coil?

Ratio of magnetic field at the centre of a current carrying coil of radius R and at a distance of 3R on its axis is

The magnetic field at the centre of a circular coil of radius r carrying current l is B_(1) . The field at the centre of another coil of radius 2r carrying same current l is B_(2) . The ratio (B_(1))/(B_(2)) is

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