Physics 1

6. When a wave slows down or speeds up due to travelling in a more or less dense medium.
7. Part of the electromagnetic spectrum with a wavelength just below radio waves
8. The amount of radiation a person has absorbed.
13. When a spring is stretched and does not return to its original shape.
15. The negatively charged particle in an atom
17. An object that can attract anything made from iron, steel, nickel or cobalt
18. The point of an object that all of its mass can be thought as being centred on.
20. An electrical device whose reistance decreases when it gets hotter.
21. Mass divided by volume
22. Also called infra red radiation - a form of radiation that is given out by hot objects.

1. A power station that uses tidal power. Usually built across an estuary.
2. A substance that allows electricity or thermal (heat energy) to pass through it easily.
3. The rate of flow of charge
4. The distance between the focus and the point where the converging rays meet.
5. A unit for measuring electricity, sometimes simply called "units"
8. The time it takes someone to react to a stimulus
9. A temporary magnet that has been "made" using a permanent magnet
10. The speed a wave moves with
11. A source of background radiation.
12. A lens that converges (brings together) rays of light.
14. A device that transmits light using the process of total internal reflection.
16. A nuclear reaction that happens in stars when small nuclei (usually hydrogen) are combined to form larger nuclei (i.e. helium)
19. One of the three wires in a plug - coloured green and yellow