An electromagnetic wave coming from infinity, enters a medium from the vacuum. For this Wave .......... is independent of the medium. [will not change in the medium] choose the correct option from the given options.
(A) ω
(B) k
(C) ω/k
(D) λ
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(D) λ
If the wave is in a vacuum, nothing changes other than amplitude and phase your beam spreads out.
If the wave enters a second material, everything can change including frequency! In order for frequency to change, that second material must either be moving or be a nonlinear material. If the second medium has a refractive index other than 1.0, the speed and wavelength of the wave will change. Polarization will change if the medium is anisotropic or if the angle of incidence is not 0∘∘. Direction can change too in many ways if the medium is anisotropic, if the wave is incident at something other than 0∘∘, if there is a grating at the interface, if the second medium is nonlinear, and probably more.
In the simplest configuration FREQUENCY is the thing that is constant. Speed and wavelength change.
If the wave is in a vacuum, nothing changes other than amplitude and phase your beam spreads out.
If the wave enters a second material, everything can change including frequency! In order for frequency to change, that second material must either be moving or be a nonlinear material. If the second medium has a refractive index other than 1.0, the speed and wavelength of the wave will change. Polarization will change if the medium is anisotropic or if the angle of incidence is not 0∘∘. Direction can change too in many ways if the medium is anisotropic, if the wave is incident at something other than 0∘∘, if there is a grating at the interface, if the second medium is nonlinear, and probably more.
In the simplest configuration FREQUENCY is the thing that is constant. Speed and wavelength change.
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