Consider a long solenoid of radius `R` which has `n` turns per unit length. A time dependent current `I=I_(0) sin omegat` flows solenoid, magnitude of electric field at a perpendicular distance `rltR`, from the axis of symmetry of solenoid is found to be `E=(alpha)/4omegamu_(0) nI_(0)r cosomegat`, where `alpha` is pure number and `mu_(0)` is permability of free space. Find `alpha`

Options

A. `mu_0 pi b^2 n_1n_2L`
B. `mu_0 pi a^2 n_1n_2L^2`
C. `mu_0 pi a^2 n_1n_2 L`
D. `mu_0 pi b^2 n_1n_2 L^2`

Answer

C

Explanation

The mutual inductance of the system is
`M = mu_0 n_1n_2pia^2 L`