When is plotted versus time for a certain isotope

CHEMISTRY · Single correct · US High School · Chemistry · Atomic Structure & Nuclear · Atomic Structure & Nuclear

Problem

When

\ln(\text{activity})

is plotted versus time for a certain isotope, the straight line passes through the points

(t=0,\,\ln A_{0})

and

(t=6.0\,\text{h},\,\ln\left(\frac{A_{0}}{8}\right))

. Which value is closest to the isotope’s half-life? (a)

3.0\,\text{h}

(b)

4.6\,\text{h}

(c)

2.0\,\text{h}

(d)

2.9\,\text{h}