Explain Doppler Effect in light and this equation.........?

Doppler Effect Light:
The apparent change in the frequency due to relative motion between the source and observer is
called Doppler Effect.
If ‘v’ is the actual frequency and ‘ ν ' ’ is the apparent frequencies, then the relative change in
frequency
∆ν/v=−ν/c
Here ‘c’ is the speed of light and ‘v’ is the velocity of the source which is small compared to
that of light. Doppler Effect in light is symmetric.
Red Shift and Blue Shift: - Apparent wavelength > Actual Wavelength.
Hence the spectrum of the radiation from the source of light shifts towards the red end of
spectrum. When a star is moving away from the Earth the wavelength increases and it looks
more reddish. This is red shift phenomenon. When the waves are received from a source
moving towards the observer, there is an apparent decrease in wavelength. This is called blue
shift.