DP Physics (first assessment 2025)
Question 23M.2.HL.TZ2.9cii
| Date | May 2023 | Marks available | [Maximum mark: 3] | Reference code | 23M.2.HL.TZ2.9cii |
| Level | HL | Paper | 2 | Time zone | TZ2 |
| Command term | Determine | Question number | ii | Adapted from | N/A |
ii.
[Maximum mark: 3]
23M.2.HL.TZ2.9cii
(ii)
A sample of glass is irradiated with neutrons so that all the magnesium atoms become magnesium-27. The sample contains 9.50 × 1015 magnesium atoms.
The decay constant of magnesium-27 is 1.22 × 10−3 s−1.
Determine the number of aluminium atoms that form in 10.0 minutes after the irradiation ends.
[3]
Markscheme
N10 = 9.50 × 1015 × e−0.00122×60 seen ✓
N10 = 4.57 × 1015 ✓
So number of aluminium-27 nuclei = (9.50 – 4.57) × 1015 = 4.9(3) × 1015 ✓
