2024 · M/J · 5054/22 | Q9

0/45parts marked · 0 of 80 marks

Question (9 of 9)9 marks · Practise this topic →

Options

Theory: answer all nine questions. Show working and appropriate units; diagrams and alternative valid methods are marked against the original scheme.

(a)Alpha particles are sometimes emitted from radioactive nuclei. Explain what spontaneous emission means.

Answer guidance

Explain Give reasons, not just what happens. Each distinct reason is usually worth a mark.

[1 mark]

(b)Describe the composition of an alpha particle.

Answer guidance

Describe Say what happens, in order. Reasons are not required unless the question also asks why.

[2 marks]

(c)(i)Describe the structure of either a cloud chamber or a spark counter used to detect alpha particles, including a labelled drawing.

Answer guidance

Describe Say what happens, in order. Reasons are not required unless the question also asks why.

[3 marks]

(c)(ii)Using the cloud chamber or spark counter you chose in 9(c)(i), describe what shows alpha emission is random.

Answer guidance

Using You must use the thing it names. An answer that reaches the right value another way may not score.

[1 mark]

(c)(iii)A cloud chamber records 120 alpha tracks/min; 6.0 hours later the same source gives 15 tracks/min, with zero background tracks. Calculate the isotope half-life.

Answer guidance

Calculate Show your working. The method can earn marks even when the final value is wrong, and a bare answer often cannot.

[2 marks]

5054/22/M/J/24Cambridge O Level Physics 5054 · May/June 2024 · Paper 2 variant 2 · Question 9