Answer:
The correct answer is - 75 grams.
Explanation:
Half-life is the amount of time that is used by the given amount of substance or element to make it half of the initial amount of a particular radioactive substance.
Equation for alpha decay for radon
[tex]^222_{86}Rn\Rightarrow^{218}_{84}Po [/tex]
we need to calculate the left amount of radon after given time
using formula half life
[tex]N(t)=N_{0}e^{-\lambda t}[/tex]
[tex]\lambda =\dfrac{0.693}{3.82}[/tex]
[tex]\lambda=0.1814[/tex]
[tex]N(3.82)=150\times e^{-0.1814\times3.82}[/tex]
[tex]N(3.82)=75.0\ g[/tex]
Thus, the left amount of radon is - 75 grams.
