16. Define the following terms: (a) Focal length (b) Principal focus (c) Center of curvature
17. Define the term “reflection.”
18. Define the term “refraction.”
19. Justify: (a) The Radius of curvature of the concave mirror will be always negative. (b) The Radius of curvature of the convex mirror will be always positive.
The law of reflection states that the angle of incidence is equal to the angle of reflection, measured from the normal (a line perpendicular to the surface) at the point of incidence.
