Question

The amount A (t), in grams, of radioactive material in a sample after years, is given

by A^t=80(2^(-t/100)

(a) Find the amount of material in the original sample /1mrks

(b) calculate the half-life of the material. (The half-life is the time taken for half of

the original material to decay).

Answer 1

(a) $A(0)=80*2^{-\frac{0}{100}}=80.$

(b) $40=80*2^{-\frac{t}{100}}$

$2^{-1}=2^{-\frac{t}{100}}$

$\frac{t}{100}=1$

$t=100$

Half-life is 100 years