The half-life of cobalt-60 is 5.26 years. After 10.52 years, 5 grams of a 20-gram sample will remain is TRUE
Explanation:
Mass of cobalt = 20 g
Half-life = 5.26 years
Mass remains after 10.52 years = 5 g
This can be solved by using given below formula, [tex]m(t)=m_{o}\left(\frac{1}{2}\right)^{\frac{l}{5.26}}[/tex]
[tex]m_{0}[/tex] = initial mass
t = number of years from when the mass was m_0
m(t) = remaining mass after t years
Number of half-lives = [tex]\frac{\text { Time elapsed }}{\text { Half -life }}[/tex]
Number of half-lives = [tex]\frac{10.52 \text { years }}{5.26 \text { years }}[/tex]
Number of half-lives = 2
At time zero = 20 g
At first half-life = [tex]\frac{20\ g}{2}[/tex] = 10 g
At second half life = [tex]\frac{10\g}{2}[/tex] = 5 g
The given statement is true.
