A radioactive sample initially contains nuclei of a certain isotope whose half-life is

PHYSICS · Single correct · A Level · Physics · Nuclear physics · Nuclear physics

Problem

A radioactive sample initially contains

1.0\times10^{4}

nuclei of a certain isotope whose half-life is

3\,\text{h}

. Exactly after

3\,\text{h}

, the sample is injected with another

2.0\times10^{3}

nuclei of the same isotope. How many nuclei of the isotope will remain undecayed after a further

3\,\text{h}

? (a)

4.5\times10^{3}

(b)

2.5\times10^{3}

(c)

3.5\times10^{3}

(d)

3.0\times10^{3}