2023 · Specimen · 0625/04 | Q10

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Question (10 of 12)6 marks · Practise this topic →

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Available practice: 75 of 80 marks. Parts 3(b), 6(a)(i) await marking support. Scores cover available parts only.

An americium (Am) nucleus decays by the emission of an α-particle into a neptunium (Np) nucleus.

Complete the nuclear equation for this decay.

(a)(i)²⁴¹₉₅Am →

Answer guidance

Complete Fill in every gap. A partly completed answer usually scores partly.

[2 marks]

Americium is used in smoke detectors.

(a)(ii)Explain why beta (β) emitters or gamma (γ) emitters are not used in smoke detectors.

Answer guidance

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

[1 mark]

The half-life of an americium nuclide is 470 years. A sample of this nuclide contains 8.0 × 10¹⁴ atoms. After some time, 6.0 × 10¹⁴ americium atoms have decayed.

(b)Calculate the time required for this decay.

Answer guidance

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

[3 marks]

0625/04/SP/23Cambridge IGCSE Physics 0625 · Specimen 2023 · Paper 4 · Question 10