Q25. Question Answer Acceptable answers Mark Number (a) Any two from the following credit any specific examples but points smoke alarms (1) must be from two different • irradiating food (1) areas for 2 marks • dating (e.g. radiocarbon) • (1) sterilisation of • equipment (1) tracing • and gauging thickness (1) (2) Question Answer Acceptable answers Mark Number (b) C (1) Question Answer Acceptable answers Mark Number (c)(i) (fast moving) electron (1) Question Answer Acceptable answers Mark Number (c)(ii) half life = 8 days (1) 24 bald 3 half lives for 2 marks days = 3 half lives (1) 12.5 give full marks for correct (mg) (1) answer, no working (3) Question Answer Acceptable answers Mark Number (d) A description including idea of planning for conditions three of the following points hundreds /thousands of the long time taken for from now public do not want • decay (of long-lived waste buried near where they radionuclides) water live (so limitation on available • causing corrosion / leaks sites) transportation of • radioactive material need • for geologically stable rock formation public • perception of waste security from terrorist • activity (3) Q26. Answer Acceptable answers Mark (a) A description to include (move) until a leak/high reading name of detector / move  is found detector over the ground (1) where leak is, there will be an  increased rate (1 (2) (b) D It is the time it takes for half (1) the atoms to decay (c)i 1.9-2 (days) (1) (c)ii Ignore any part of line after 4
Q25. Question Number Answer Acceptable answers Mark (a) Any two from the following points • smoke alarms (1) • irradiating food (1) • dating (e.g. radiocarbon) (1) • sterilisation of equipment (1) • tracing and gauging thickness (1) credit any specific examples but must be from two different areas for 2 marks (2) Question Number Answer Acceptable answers Mark (b) C (1) Question Number Answer Acceptable answers Mark (c)(i) (fast moving) electron (1) Question Number Answer Acceptable answers Mark (c)(ii) half life = 8 days (1) 24 days = 3 half lives (1) 12.5 (mg) (1) bald 3 half lives for 2 marks give full marks for correct answer, no working (3) Question Number Answer Acceptable answers Mark (d) A description including three of the following points • the long time taken for decay (of long-lived radionuclides) • water causing corrosion / leaks • transportation of radioactive material • need for geologically stable rock formation • public perception of waste • security from terrorist activity idea of planning for conditions hundreds /thousands of from now public do not want waste buried near where they live (so limitation on available sites) (3) Q26. Answer Acceptable answers Mark (a) A description to include  name of detector / move detector over the ground (1)  where leak is, there will be an increased rate (1 (move) until a leak/high reading is found (2) (b) D It is the time it takes for half the atoms to decay (1) (c)i 1.9-2 (days) (1) (c)ii Ignore any part of line after 4
p2_revision_pack_mark_scheme.docx