Two coaxil solenoids 1 and 2 of the same length are set so that one is inside the other. The number of turns per unit length are `n_(1)` and `n_(2)`. The current `i_(1)` and `i_(2)` are flowing in opposite directions. The magnetic field inside the inner coil is zero. This is possible when

A toroid has number of turns per unit length n , current i , then the magnetic field is

There are two long co-axial solenoids of same length l. The inner and other coils have redii r_(1) and r_(2) and number of turns per unti length n_(1) and n_(2) respectively .The reatio of mutual inductance to the self - inductance of the inner- coil is :

There are two long co-axial solenoids of same length l. The inner and other coils have redii r_(1) and r_(2) and number of turns per unti length n_(1) and n_(2) respectively .The reatio of mutual inductance to the self - inductance of the inner- coil is :

Two coaxial long solenoids of equal length have current, i_(1), i_(2) , number of turns per unit length n_(1), n_(2) and radius r_(1), r_(2) respectively. If n_(1)i_(1)=n_(2)i_(2) and the two solenoids carry current in opposite sense, the magnetic energy stored per unit length is [r_(2)gt r_(1)]

Two coaxial long solenoids of equal length have current, i_(1), i_(2) , number of turns per unit length n_(1), n_(2) and radius r_(1), r_(2) respectively. If n_(1)i_(1)=n_(2)i_(2) and the two solenoids carry current in opposite sence, the magnetic energy stored per until length is [r_(2)gt r_(1)]

In a toroid the number of tuns per unit length is 1000 and current through it is 1/(4pi) ampere. The magnetic field produced inside (in "weber"//m^(2) ) will be

In a toroid the number of tuns per unit length is 1000 and current through it is 1/(4pi) ampere. The magnetic field produced inside (in "weber"//m^(2) ) will be