JAMB Chemistry 2024 Paper

$\frac{\text{Original mass}}{2^n}$ = Residual mass

Where n = number of activity = $\frac{\text{exposure time}}{\text{half life}}$

Given:

Original mass = 1g, exposure time = 10 minutes , half life = 2 minutes, Residual mass = ?

Substituting all the given parameters appropriately, we have

n = $\frac{10}{2}$

n = 5

$\frac{\text{Original mass}}{2^n}$ = Residual mass

$\frac{1}{2^5}$ = Residual mass

$\frac{1}{32}$ = Residual mass

Residual mass = $\frac{1}{32}$ or 0.03125g