Question
Two circular coils, one of radius r and the other of radius R are placed coaxially with their centres coinciding. For R >> r, obtain an expression for the mutual inductance of the arrangement.
Solution
Given, two circular coils one of radius 'r' and the other of radius 'R' placed coaxially with their centers coinciding.
Suppose a current I2 flows through the outer circular coil.
Magnetic field at the centre of the coil is
Magnetic field B2 may be considered constant over the cross-sectional area of the inner smaller coil.
Hence,
Suppose a current I2 flows through the outer circular coil.
Magnetic field at the centre of the coil is
Magnetic field B2 may be considered constant over the cross-sectional area of the inner smaller coil.
Hence,