In a semi-log plot (natural logarithm) of activity versus time for a radioactive isotope

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

Problem

In a semi-log plot (natural logarithm) of activity

A

versus time

t

for a radioactive isotope, the straight line has a slope of

-0.045\,\text{min}^{-1}

. The half-life

t_{1/2}

of the isotope is closest to (a)

7.0\,\text{min}

(b)

15\,\text{min}

(c)

22\,\text{min}

(d)

31\,\text{min}