DP Physics (first assessment 2025)

Question EXE.2.HL.TZ0.21ci

Date	Example questions Example questions	Marks available	[Maximum mark: 3]	Reference code	EXE.2.HL.TZ0.21ci
Level	HL	Paper	2	Time zone	TZ0
Command term	Calculate	Question number	i	Adapted from	N/A

[Maximum mark: 3]

EXE.2.HL.TZ0.21ci

(i)

Calculate the energy released when one mole of strontium-90 decays to 2% of its original activity forming the stable daughter product.

[3]

Markscheme

Idea that the Yttrium half life is much less than Strontium so can assume all Yttrium energy is included. ✓

$0.98 \times 6.02 \times 10^{23} \times (0.52 + 2.3) \times 10^{6}$ seen ✓

$(= 1.67 \times 1030 eV)$

Answer $\times 1.6 \times 10^{- 19} = 270$ GJ ✓

Syllabus sections