Atomic Physics

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Across
  1. 1. scientist who first showed the nucleus had a concentrated mass and charge
  2. 3. least penetrating radioactive emission
  3. 4. particle which has a mass of 1 and a charge of +1
  4. 8. time required for a quantity to reduce to half of its initial value
  5. 10. radioisotope found in smoke detectors
  6. 13. least penetrating radioactive emission
  7. 16. most used radioisotope in diagnostic imaging
  8. 18. represented by lambda in decay calculations
  9. 20. when electrons lose energy and fall to lower shells
Down
  1. 2. scientist who first showed the atom was made of smaller things
  2. 5. if it has an unstable ratio or protons and neutrons
  3. 6. the effect of a material emitting electrons when exposed to light
  4. 7. name of the constant which links E with f
  5. 9. a fundamental particle with a relative mass of 0.0005u
  6. 11. your physics teacher's first name
  7. 12. the units when you divide the energy in joules by 1.6x10-19
  8. 14. used to test the integrity of pipeline welds
  9. 15. a fast-moving electron
  10. 17. the length of a wave
  11. 19. the fundamental particles that make up protons & neutrons