Answer
a. h is the time needed for the initial quantity to decay to half its value.
b. $m(t)=m_{0}e^{-\frac{t\cdot\ln 2}{h}}$
c. $r=\displaystyle \frac{\ln 2}{h}$
d. $m(t)=m_{0}e^{-rt}$
Work Step by Step
Radioactive Decay Model is described on pages 375-376$:$
If a radioactive substance with half-life $h$
has initial mass $m_{0}$,
then at time $t$
the mass $m(t)$ of the substance that remains
is modeled by the exponential function
$m(t)=m_{0}e^{-rt} $where $r=\displaystyle \frac{\ln 2}{h}$.
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a.
Half-life h is the TIME needed for the initial quantity to decay to half its value.
b. See page 376,
$m(t)=m_{0}e^{-rt},\ \quad $where $r=\displaystyle \frac{\ln 2}{h}$.
So,
$m(t)=m_{0}e^{-\frac{t\cdot\ln 2}{h}}$
c. $r=\displaystyle \frac{\ln 2}{h}$
d. $m(t)=m_{0}e^{-rt}$
