11. The image formed in front of the mirror. 12. The image formed behind the mirror.
13. The image formed below the optical axis.
14. The image formed above the optical axis.
15. The left-right reversal in mirror imaging.
16. A converging mirror.
17. A diverging mirror.
18. The bouncing back of light into the same medium it has been travelling after striking a surface.
19. The ratio of the speed of light in a vacuum to that in the substance.
20. The change in the direction of light when it passes from one medium to another of different optical
densities.​