Answer:
61 hours
Explanation:
In this question we will use radioactive decay model
[tex]m(t)=m_02^{-\frac{t}{h}}[/tex]
m0= 250 mg
h is the hlf life of element
m(t) is the mass left after t time
so,
[tex]198=250\times2^{-\frac{24}{h}}[/tex]
solving this equation for h
reaaranging and taking ln on both the sides we get
[tex]ln2^{-\frac{24}{h}}= ln(\frac{190}{250})[/tex]
solving further we get
h= 60.62 hours ≅61 hour
the half life of element is 61 hours
