Across
- 4. the time it takes for half of the atoms in a radioactive sample to decay
- 5. another word for 'size'
- 8. a quantity that has size only
- 11. type of radiation made of protons and 2 neutrons
- 12. the units for frequency
- 13. when radioactive material gets into or onto a person
- 14. the speed of an object and its direction
- 15. the number of waves passing a point in one second
- 16. the unit for measuring radiation
- 17. the distance from one point on a wave to the same point on the next wave
- 19. the units for power
- 21. the name of the old model of the atom with no nucleus
- 22. thermal ____________ the amount of energy a material lets pass through it
- 23. the distance in a straight line from the start of a journey to the end
- 24. the energy store of something that is moving
Down
- 1. when something is exposed to radioactivity
- 2. in Rutherfords experiment he fired alpha particles at a piece of foil made of this material
- 3. the percentage of input energy that is transferred usefully
- 6. the maximum displacement of a point on a wave from its rest position
- 7. type of radiation made of an electron
- 9. the rate of change of velocity
- 10. a quantity that has size and direction
- 18. a high frequency EM wave
- 20. a spectrum of transverse waves made of 7 sections that travel at the speed of light