Useful Equations

Relationship between frequency and wavelength:

Wavelength(in cm) = c / Frequency(in Hz)

Frequency (in Hz) = c / Wavelength (in cm)

where c = 3 × 10¹⁸ cm/s

Doppler Equation:

Observed frequency = Emitted frequency × (1 - Velocity/c)

Velocity =c × (1 - Observed frequency / Emitted frequency)

Note: Velocity is > 0 if object is moving away from us; .Velocity is < 0 if object is moving toward us