A counter recording radioactive decays from a radioactive source gives the following counts in equal intervals of time. [Table showing time/min and counts: 0-10: 424, 10-20: 395, 20-30: 413, 30-40: 363, 40-50: 366, 50-60: 294, 60-70: 301, 70-80: 253, 80-90: 212] What can be deduced from these readings?
✓ Correct Answer
The correct answer is B: that radioactivity is random and that the half-life is uncertain
📋 Examiner Report & Trap Analysis
Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...
🎯 Mark Scheme Breakdown
Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.
Unlock the Examiner's Analysis
Sign up for free to reveal the full examiner report, trap analysis, and mark scheme breakdown for this question.
Sign Up Free to Unlock →Join thousands of Cambridge students already using Oracle Prep