GCSE Perfect
Calculate — 2 marks
A hospital uses Technetium-99m as a tracer to diagnose medical conditions. Technetium-99m has a half-life of 6 hours. A patient is given an initial dose of 800 MBq (megabecquerels) of the radioactive isotope.
- Calculate the activity of Technetium-99m remaining in the patient's body after 12 hours. [2 marks]
Show mark scheme
- {'mark': 1, 'description': 'Correctly identifies that 12 hours = 2 half-lives (or equivalent working showing division of 12 by 6)'}
- {'mark': 1, 'description': 'Correctly calculates final activity as 200 MBq (showing either 800 ÷ 2 ÷ 2 or 800 × (1/2)²)'}