DP Physics (first assessment 2025)

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Question EXE.2.HL.TZ0.21b

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Date Example questions Example questions Marks available [Maximum mark: 2] Reference code EXE.2.HL.TZ0.21b
Level HL Paper 2 Time zone TZ0
Command term Determine Question number b Adapted from N/A
b.
[Maximum mark: 2]
EXE.2.HL.TZ0.21b
(b)

Strontium-90 is a waste product from nuclear reactors that has a decay constant of 7.63 x 10−10 s−1. Determine, in s, the time that it takes for the activity of strontium-90 to decay to 2% of its original activity.

[2]

Markscheme

ln 0.02=-7.63×10-10t or equivalent seen ✓

t=5.1 Gs ✓

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