A student is modelling the decay of a short-lived radioactive tracer using a spreadsheet simulation based on the discrete equation:
ΔNΔt=−0.3N \frac{\Delta N}{\Delta t} = -0.3 N ΔtΔN=−0.3NThe student uses a time step of Δt=0.50 s\Delta t = 0.50\text{ s}Δt=0.50 s. The initial number N N\,N of radioactive nuclei is 8000 at t=0t = 0t=0.
An extract of the student's modelling spreadsheet is shown below.
| t/st / \text{s}t/s | Number N N\,N of radioactive nuclei remaining at time ttt | Number of nuclei decaying in the next 0.50 s |
|---|---|---|
| 0 | 8000 | 1200 |
| 0.50 | 6800 | |
| 1.00 | ||
| 1.50 |
What is the modelled value of N N\,N at t=1.50 st = 1.50\text{ s}t=1.50 s?
274427442744
491349134913
510151015101
578057805780
90 exam-style questions on OCR A A Level Physics Nuclear and particle physics, covering The nuclear atom, Fundamental particles, Radioactivity, and Nuclear fission and fusion. Each one has a worked solution and a mark scheme showing where the marks go.