IB Physics HL E 3 19 Hl Radioactive Decay Law Questions

Apply the HL radioactive decay law to calculate remaining nuclei, decay fractions and ages from half-life or decay-constant data.

Exam points

apply N=N0e^(-λt) to calculate remaining nuclei, decayed fractions and expected counts after a stated time
solve radioactive-dating problems by relating measured parent or daughter amounts to elapsed time
use decay constant, half-life and exponential data consistently, including appropriate units and significant figures

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Study E.3.19 (HL)—Radioactive decay law conceptsOpen the corresponding Concept lesson for explanations, examples and exam connections.

[Maximum number: 3]

This question is in two parts. Part 1 is about kinematics and gravitation. Part 2 is about radioactivity.

Part 1 Kinematics and gravitation

A ball is released near the surface of the Moon at time t=0. The point of release is on a straight line between the centre of Earth and the centre of the Moon. The graph below shows the variation with time t of the displacement s of the ball from the point of release.

Figure for Question IB Physics HL E 3 19 Hl Radioactive Decay Law Questions question 1 — IB Physics HL

In a pure sample of lead-212 at one instant, $8.0 \times 10^{-3} \mathrm{~kg}$ of the lead-212 is present. Calculate the mass of lead-212 that remains after a period of 35 hours.

use of $\lambda$ from (h)(i);
correct substitution into $N=N_{0} \mathrm{e}^{-\lambda t}$ ;
8.0 to $8.3 \times 10^{-4} \mathrm{~kg}$ ;

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IB Physics HL E 3 19 Hl Radioactive Decay Law Questions question 1