radiation

• What is the process called when an unstable atomic nucleus gives out radiation to become more stable?


  Radioactive decay
• What does the term 'activity' refer to in the context of unstable nuclei?


  It refers to the rate at which a source of unstable nuclei decays
• In what unit is activity measured?

  Becquerel (Bq)
• What is count-rate in the context of nuclear decay?


  It is the number of decays recorded each second by a detector
• What is an alpha particle composed of?


  Two neutrons and two protons
• What is a beta particle?


  A high-speed electron ejected from the nucleus as a neutron turns into a proton
• What type of radiation is a gamma ray?


  Electromagnetic radiation from the nucleus
• what happens to mass number and charge of nucleus when beta emitted?


  mass stays same but charge increases
• why is it difficult to detect gamma radiation?


  because it is weakly ionising
• What is half life?


  the half life of an isotope is the amount of time take for the activity of the sample to halve
• Explain why the count rate was less than the activity of the sample of lanthanum-40


  because radiation goes in all directions and only some goes into the geiger muller tube
• Explain why the teacher stood far away from the gamma radiation practical?- 2 marks


  to reduce irradiation exposure and risk of cancer
• State two environmental issues caused by generating electricity using nuclear power stations.


  • long half life
  • radioactive
• 3 things to talk abt with graph questions asking to describe

  • rate
  • level off?
  • overall change
• The half-life of the radioactive source used was very short.

  Give one reason why this radioactive source would be much less hazardous after 800 seconds.


  very small amount of radiation emitted