Question

Consider the self-inductance per unit length of a solenoid at its centre and that near its ends. Which of the two is greater?

Answer 1

Self-inductance per unit length of solenoid is given as,
$\frac{L}{l}={\mu }_0{n}^{2}A$

From the above equation we can see that, self inductance per unit length will depend on the permeability of free space (${\mu }_0$), number of turns per unit length (n) and area of the cross-section of the solenoid (A). All the above factors are constant at the centre and near any end of the solenoid therefore self inductance at both the points will be same.