What is the value of permeability of free space?

The area of B - H loop for a ferromagnetic material is 540 J m^-3 . If the absolute permeability of free space is 4pi xx 10^-7 J A^-2 m^-1 , find the area of the I - H loop of the ferrogmangnetic material.

Write down the value of absolute permittivity of free space (vaccum).

what is membrane permeability?

What is the velocity of e.m. waves in free space?

If absolute permittivity and permeability of free space are epsilon_0 = 8*85 xx 10^(-12) C^2 N^(-1) m^(-2) and mu_0 = 4 pi xx 10^(-7) N s^2 C^(-2) .Caculate the velocity of electromagnetic waves?