Question

If the light moving in a straight line bends by a small but fixed angle, it may be a case of 
(a) reflection
(b) refraction
(c) diffraction
(d) dispersion.

Answer 1

(a) reflection
(b) refraction

When the light strikes on a surface nearly parallel to it, it then bends by a small and fixed angle after reflection. Also, when the light travels from one medium to another with slight differences in their refractive indices, it bends by a small angle. Thus, the bending of light by a small but fixed angle can be the case of either reflection or refraction.