Radioactivity is the property exhibited by some unstable atoms of
elements in which from their nucleus radiation energy and subatomic
particles are simultaneously emitted.
Reason:
Known parameters:
The number of hours the sample is left, t = 3,198 hours
The given mass of radium, N₀ = 0.840 g
Required:
The mass of the fraction of the 0.840 g sample that remains after 3,198 hours.
Solution;
The half life of radium, [tex]t_{1/2}[/tex] = 1,600 years = 14,025,600 hours
The formula for finding the amount of a radioactive substance is remaining
after a given time, t, is given as follows;
Therefore;
[tex]N(t) = 0.840 \times \left (\dfrac{1}{2} \right )^{\dfrac{3198}{14,025,600}} \approx 0.839867[/tex]
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