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5.2 Radioactivity

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Question 47

A radioactive isotope has a half-life of 15 years.

A sample of the material initially contains 1.6 × 1011 atoms.

How many atomic nuclei have decayed after 45 years?

A

2.0×10102.0 \times 10^{10}2.0×1010

B

8.0×10108.0 \times 10^{10}8.0×1010

C

1.2×10111.2 \times 10^{11}1.2×1011

D

1.4×10111.4 \times 10^{11}1.4×1011

Markscheme

5.2 Radioactivity Questions

  1. IGCSE
  2. /Physics
  3. /5.2 Radioactivity

484 exam-style questions on CIE IGCSE Physics 5.2 Radioactivity, covering 5.2.1 Background radiation and measuring count rate, 5.2.2a Alpha, beta and gamma emission, 5.2.2b Deflection and ionising effects of nuclear radiation, 5.2.3a Radioactive decay, 5.2.3b Effects of decay on the nucleus and decay equations, 5.2.4a Half-life, 5.2.4b Choosing isotopes for applications, and 5.2.5 Effects of ionising radiation and safety precautions. Each one has a worked solution and a mark scheme showing where the marks go.

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