Physics 2.7

• What are the three types of radiation?

  Alpha, beta, gamma.
• What is the easiest radiation to block?

  Alpha particles
• What is alpha radiation made of?

  Helium nucleus
• What is beta radiation?

  high energy electrons
• What is gamma radiation?

  Electromagnetic waves
• What stops alpha radiation?

  Paper
• What stops beta radiation?

  a few mm of aluminium
• What stops gamma radiation?

  A few cm of lead
• What are isotopes?

  Isotopes are atoms of the same element that have different numbers of neutrons.
• What do unstable nuclei do to become more stable?

  Undergo radioactive decay (release some radioactive emissions)
• When do alpha emissions occur?

  When a nucleus decays by emitting a helium nucleus consisting of 2 protons and 2 neutrons
• What is beta decay?

  Where a neutron in an unstable atom changes to a proton and emits a high energy electron
• When do gamma emissions occur?

  When a nucleus releases some energy in the form of an electromagnetic wave
• What does ionising radiation cause?

  Damage to body cells
• When measuring radioactive decay why must you take repeat readings and calculate a mean?

  Because radioactive decay is a random and spontaneous process
• How can we increase the reliability when measuring radioactive decay?

  •measure the rate over a longer time period such as 10minutes

  •repeat the experiment
• What does background radiation come from?

  1• radon gas

  2• rocks

  3• buildings

  4• food

  5• cosmic radiation

  6• medicine

  7• nuclear power and testing
• What is background radiation?

  Radiation that is present in the environment from natural and artificial sources.
• What radiation is able to penetrate the body?

  Gamma
• Which radiation is the most ionising?

  Alpha
• Why is the background radiation count higher in some parts of the country than others?

  There may be more radon due to different types of rocks