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.​

massxgravity x heght=weightxheight= pe

4900=490xh

h=10

chemical energy --> gravitational potential energy --> kinetic energy --> elastic potential energy --> gravitational potential energy

explanation:

when emma starts the hike, the chemical energy stored in her body is used to climb up the mountain, and so she gains gravitational potential energy (because at the end, she will be at a higher height h above the ground). then she goes bungee jumping: as she falls, this gravitational potential energy is converted into kinetic energy (because her speed increases as she falls down), until the point when the rope stretches, and she stops moving. at that moment, all the kinetic energy is converted into elastic potential energy due to the stretching of the rope. then, this energy is released because the rope returns to its natural length, and emma gains a small increase in altitude , so she gains some gravitational potential energy.