Vacuum Impedance: Physical Origin Explained

[Kolahal Bhattacharya]

The vacuum impedance,as our professor writes in blackboard, equals 377 ohm
What is the physical origin of this impedance?

 

[J Hann]

This value arises from the plane wave solution of Maxwell's equations.
The ratio of E/H in a plane wave in free space is equal to the square
root of the ratio of the magnetic permittivity (mu) to the electric permittivity (epsilon).
This value has the dimensions of ohms and is called the characteristic
impedance of free space and has the value of 376.6 ohms.