Radioactive decay

• Radioactive decay is when an unstable nucleus changes to become more stable and gives out radiation
• Activity is the rate at which decay occurs measure in becquerels ( Bq )
• Count rate is the number of decays recorded each second by a Geiger-Muller tube
• Unstable nuclei give out radiation to make themselves more stable . This random process is called radioactive decay
• If a source of radioactive nuclei is very unstable it will have a high activity for example 1,000,000 Bq . This means 1,000,000 nuclei are decaying each second etc.
• The activity of a radioactive source can be plotted against time . Over time the activity decreases this is because there are fewer and fewer unstable nuclei left to decay as unstable nuclei eventually turn into stable nuclei.
• In radioactive decay the mass of an alpha nucleus is decreased by 4
• In radiactive decay the mass of an beta nucleus is decreased by 0
• In radiactive decay the mass of a gamma nucleus is not decreased
• In radioactive decay the alpha particle has a positive charge reduced by -2
• In radioactive decay the beta particle has a positive charge increased by 1
• The Geiger muller tube is used to detect nuclear radiation