Use the worked example above to help you solve this problem. The half-life of the radioactive nucleus _(88)^(226)text(Ra) is 1.6 103 yr. If a sample initially contains 4.00 1016 such nuclei, determine the following:. (a) the initial activity in curies µCi
(b) the number of radium nuclei remaining after 4.4 103 yr nuclei
(c) the activity at this later time µCi

Explanation:

From the information given:

The half-life = 1.6103 years

The no. of the initial nuclei =

Using the formula:

where;

decay constant

∴

The number of radium nuclei N = 5.94 × 10¹⁵

The initial activity

Since;

1 curie = 3.7 × 10¹⁰ Bq

Then;

c) The activity at a later time is:

pythagoras' theorem

square root (-5^2+9^2)

square root (25+81)

square root (106)

angle is tan^-1(9/5)

neg x, pos y