HideShow resource information
  • Created by: emma
  • Created on: 15-05-13 14:24

Types of nuclear radiation

Alpha - strongly ionising, slow, not very penetrating.

Beta-minus - moderatley ionising, fast, moderatley penetrating.

gamma - very weakly ionising, travels at the speed of light, very penetrating.

1 of 5

where does background radiation come from?

  • Radon gas released from rocks emits alpha radiation
  • ground and buildings: all rock contains radioactive isotopes
  • cosmic rays
  • living things: plants and animals all contain carbon, some of which is radioactive carbon 14
  • man-made radiation: makes up a very small portionof background radiation.
2 of 5

Uses of radioactive isotopes

  • Radiocarbon dating (carbon-14)
  • diagnose and treat medical problems
  • sterilise food
3 of 5

Half-life and rate of decay

  • Activity (number of atoms which decay each second) is proportional to the size of a sample.
  • decay constant (lambda) measures how quickly an isotope will decay.
  • bigger decay constant = faster rate of decay

Half-life: the average time it takes for the number of undecayed atoms to halve.(in practice it is measured by the time taken for the activity to halve)

4 of 5

Fission reactors

  • U-235 hit by thermal neutron
  • neutron absorbed
  • unstable U-236 breaks up into two smaller nuclei and some high speed neutrons
  • difference in binding energy is given off as Ek of daughter products
  • harnessed to drive electricity generating system
  • graphite/water moderator slows emitted neutrons
  • they arrive at next fuel rod at slow enough speed to be absorbed
  • cadmium/boron control rods absorb excess neutrons and prevent reaction running out of control
5 of 5


No comments have yet been made

Similar Physics resources:

See all Physics resources »See all Radioactivity resources »