Correct Answer - Option 3 : Reciprocal of the speed of light in vacuum
Concept:
In electromagnetic waves, the ratio of amplitudes of the electric field and the magnetic field is equal to the velocity of the electromagnetic waves in free space.
\(\frac{{{E_0}}}{{{B_0}}} = c\)
\(\frac{{{B_0}}}{{{E_0}}} = \frac{1}{c}\)
Where:
E0 = Electric field
B0 = Magnetic field
c = velocity
Derivation:
The intrinsic impedance of the wave is defined as the ratio of the electric field and the magnetic field phasor (complex amplitude), i.e.
\(\frac{{\left| E \right|}}{{\left| H \right|}} = \eta = \sqrt {\frac{\mu }{\epsilon}} \)
Since B = μ H
\(H = \frac{B}{\mu }\)
\(\frac{{\left| E \right|}}{{\left| B \right|}}\mu = \sqrt {\frac{\mu }{\epsilon}}\)
\(\frac{{\left| E \right|}}{{\left| B \right|}} = \sqrt {\frac{1}{{\mu\epsilon }}}\)
\(c = \frac{1}{{\sqrt {{\mu _0}{\epsilon_o}} }},\;\frac{{\left| E \right|}}{{\left| B \right|}} = c\)
