The magnitude of the magnetic field inside a long solenoid is increased by

Options

A. A)decreasing its radius
B. B)decreasing the current through it
C. C)increasing its area of cross-section
D. D)introducing a medium of higher permeability

Answer

D

Explanation

By field along the axis of a solenoid
`B = mu _(0) ni`
where B= magnetic field
`mu_(0)=` permeability of free space
`mu=` the number of turns per unit length
I = current
So, according to the formula,
The magnitude of the magnetic field inside a long solenoid is increased by introducing a medium of higer permeability