Light of wavelength 5000 Å falls on a reflecting surface. For what angle of incidence is the reflected ray normal to the incident ray?

Which is the reflected ray?

Light of wavelength 5000 Å falls on a reflecting surface. What are the wavelength and frequency of the reflected light ?

Which is the incident ray ?

Unpolarized light is incident on a plane glass surface. What should be the angle of incidence so that the reflected and refracted rays are perpendicular to each other? (Given n=1.5)

What is the relation between anlage of incidence and angle of reflection?