Two concentric and coplanar coils have redii a and `b ( gt gt a)` as shows in Fig. Resistance of the inner coil is `R`. Current in the outer coil in increased from `0` to `i`, then the total charge circulating the inner coil is

Two concentric and coplanar coils have radii a and b ( gt gt a) as shows in Fig. Resistance of the inner coil is R . Current in the outer coil is increased from 0 to i , then the total charge circulating the inner coil is

Two concentric coils carry the same current in opposite directions. The diameter of the inner coil is equal currents. The outer coil. If the magnetic field produced by the outer coil at the common centre are 1 T , the net field at the centre 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?

Two coplanar concentric circular coils of radii r and 2r, have the same number of turns n. The smaller coil carries a clockwise current i, while the larger coil carries an anticlockwise current 2i. The magnetic field induction at the centre is

Two coplanar concentric circular coils of radii r and 2r, have the same number of turns n. The smaller coil carries a clockwise current i, while the larger coil carries an anticlockwise current 2i. The magnetic field induction at the centre is