Give the expression for the magnitude of magnetic flux density along the axis of solenoid in terms of magnetic moment. Give the meaning of the symbols used.

Explanation

The magnitude of magnetic flux density at a point along the axis of a solenoid is given by,
`B = ((mu_(o))/(4pi)) (2m)/(r^(3))`
where , m = magnetic moment of the solenoid .
= N (2l) I `(pia^(2))`
`= 2pi NI la^(2)`
where 'a' is radius of the solenoid , N - number of turns . `I` - current and `2I` - length of the solenoid .