Answers to questions in the Student Book - Hodder Plus Home

GCSE Physics for CCEA second editiond) i) A beam of beta particles will all be absorbed by a sheet of aluminium several mm thickplaced in their path.(1 mark)ii)(3 marks)iii) First measure the background count rate. Then measure the count rate for increasingthicknesses of aluminium.(3 marks)iv) Increase the thickness of the aluminium between the source and the Geiger tube andmeasure the corresponding count rate until the count rate is equal to the backgroundcount. Then measure the thickness of the aluminium – this thickness is the range of betaparticles in aluminium.(2 marks)v) (2 marks)14 14 02. a)6C 7N-1β(4 marks)b) Firstly, alpha radiation is so ionisng that it is likely to cause serious harm to tissues within thebody. Secondly, alpha radiation has such a small range that it cannot leave the body and bedetected by the camera.(2 marks)c) i) Background activity comes from rocks containing uranium and other radioactiveelements, the waste products from nuclear power stations and Nuclear MedicineDepartments in hospitals and cosmic rays from space. To obtain the corrected count ratethe experimentalist subtracts the background count rate from the measured count rate.Corrected count rate = Observed count rate less Background count rate. (2 marks)20