Wavelength is also a very important component of any electromagnetic wave. Wavelength is the distance between the two successive crests or troughs. Angular width is used in diffraction phenomenon and is known as the fringe width β denoted by the symbol beta. Its expression is given as 

β= λD/d, where λ is the wavelength of source, D is the distance between two source and the screen and d is the distance between the two slits.