Question
Ray optics is valid, when characteristic dimensions are
A.
of the same order as the wavelength of light
B.
much smaller than the wavelength of light
C.
of the order of one millimetre
D.
much larger than the wavelength of light
Answer :
much larger than the wavelength of light
Solution :
Ray optics, uses the geometry of straight lines to account for the macroscopic phenomena like rectilinear propagation, reflection, refraction etc. Ray optics can be taken as a limiting case of wave optics. This is primarily because wavelength of light is small.