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7 marksRadioactivity

CAPE Physics Unit 2 · May/June 2022 · Paper 2 · Question 3(b)(i)

Iodine-123 is a radioisotope used in diagnostic imaging. A sample with an initial activity of 3000 counts per minute was administered to a patient. After 4 hours and 20 minutes, the activity decreased to 2400 counts per minute.

Calculate the half-life of Iodine-123, in hours.

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Other parts of this question

  1. 3(a)(i)Define Activity and state the unit in which it is measured.[2 marks]
  2. 3(a)(ii)Define Decay constant and state the unit in which it is measured.[2 marks]
  3. 3(a)(iii)Define Half-life and state the unit in which it is measured.[2 marks]
  4. 3(b)(ii)Determine the energy of this photon, in Joules.[2 marks]
  5. 3(c)(i)Complete Column 3 and Column 4 in Table 2.[4 marks]
  6. 3(c)(ii)On the grid provided in Figure 3 on page 19, plot a graph of ln(N/N_0) versus time, t. Draw the line of best fit through the points.[4 marks]
  7. 3(c)(iii)Readings are no longer reliable when they fall below 2100 counts per minute. Use the graph in (c)(ii) to determine the period of reliability for a sample that…[3 marks]
  8. 3(c)(iv)State TWO properties of a radioisotope which might make it suitable for use in nuclear medicine, giving an explanation in EACH case as to why that particular…[4 marks]

More practice: the rest of this paper · more Radioactivity questions · all CAPE Physics Unit 2 past papers