A laboratory requires a source that will still have an activity of exactly after…

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

Problem

A laboratory requires a source that will still have an activity of

5.0\times10^{7}\,\text{Bq}

exactly

10\,\text{h}

after manufacture. The chosen isotope has a half-life of

3.0\,\text{h}

. What minimum initial number of nuclei

N_0

must be prepared? (Take

\ln2 = 0.693

.) (a)

1.1\times10^{9}

(b)

2.2\times10^{9}

(c)

5.0\times10^{8}

(d)

2.3\times10^{8}