ridium-192 is one radioisotope used in brachytherapy, in which a radioactive sou
ID: 523401 • Letter: R
Question
ridium-192 is one radioisotope used in brachytherapy, in which a radioactive source is placed inside a patient's body to treat cancer. Brachytherapy allows the use of a higher than normal dose to be placed near the tumor while lowering the risk of damage to healthy tissue. Iridium-192 is often used in the head or breast Answer the following three questions (a, b, and c) based on the radioactive decay curve of iridium-192 shown below. Click on the graph and move the mouse over a point to get values for that point. Sample remaining 100 90 80 70 50 20 10 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 Time (days)Explanation / Answer
Half life time is the time required for the conversion of half of the initial amout of reactant ot product.
From the graph, initial amount = 100
Half of the amount = 50 , Time to reach this amount from graph = 74 days (approx.)
(a) Half life time = 74 days
k = 0.693 / t1/2 = 0.693 / 74 = 0.00936 day-1
(a) Intial amount = 100
final amount = 100 - 100 (3/4) = 25
k = 0.00936 day-1
t = ?
All radio active decay follows first order kinetics,
first order integrated rate constant equation is,
k = (1/t) * ln[A]0/[A]t
0.00936 = (1/t)*ln(100/25)
t = 148 days.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.