Physics

Problem

A radioactive sample initially contains

8.0\times10^{20}

nuclei. After

10\text{ d}

the number of undecayed nuclei is measured to be

5.0\times10^{20}

. (a) Calculate the decay constant

\lambda

of the isotope. (b) Determine the number of undecayed nuclei expected to remain after

25\text{ d}

. (c) On clearly labelled axes, sketch the straight-line graph you would obtain if you plotted

\ln N

against

t

from

t=0

t=25\text{ d}

, marking the numerical values of the slope and the intercept. a. (a) Calculation of

\lambda

b. (b) Number of nuclei after

25\text{ d}

c. (c) Qualitative sketch of

\ln N

versus

t

with slope and intercept