Answer:
ray optics and wave optics. Here's the complete question
Although the transmission of light, and electromagnetic radiation generally, is correctly described by wave (physical) optics, there are situations for which ray (geometric) optics gives a sufficiently good approximation. For each of the situations described in the following, determine whether ray optics may be used or wave optics must be used.
50% part (a) Green laser light of wavelength 530 nm is incident on a 26-cm diameter mirror.
50% part (b) Red laser light of wavelength 722 nm is incident on a molecule of size 114 nm.
Explanation:
a) the answer is ray optics because when the mirror which is a macroscopic object interacts with the green laser light, a part of the light will be reflected by the mirror and the other part will be transmitted. mirror,lenses are examples of objects that deal with ray optics and they are based on rectilinear propagation of light.
b) the answer is wave optics because it will interfere with the light emitted by the red laser light and the molecule size is very minute. wave optics deals with interference, polarization, diffraction,, and other phenomena for which the ray approximation of geometric optics is not valid.