DP Physics (first assessment 2025)

Question 19M.2.HL.TZ2.ci

ci.

[Maximum mark: 2]

19M.2.HL.TZ2.ci

Estimate, in Bq, the initial activity of the sample.

[2]

Markscheme

number of nuclei is $\frac{{28 \times {{10}^{ - 3}}}}{{64}} \times 6.02 \times {10^{23}}/2.63 \times {10^{20}}$ ✔

$A =$ « $\lambda N = 2.63 \times {10^{20}} \times \frac{{5.5 \times {{10}^{ - 2}}}}{{3600}}$ » $4.0 \times {10^{15}}$ «Bq» ✔

Examiners report

Many scored the first mark for calculating the number of nuclei but neglected to convert λ to s^-1.

Syllabus sections