Question

Barium-131 is a radioactive isotope of the element barium used for gastrointestinal tract scans in doctors offices. Barium-131 has a half-life of 10 days. If a patient drinks 2 grams of barium-131 how much of the isotope will be left after 10 days?

A) 0.125 grams B) 0.25 grams C) 0.5 grams D) 1 gram

Answer 1

After 10 days 1 gram is left.

Answer 2

Answer:The correct answer is option D.

Step-by-step explanation:

Amount of dose given to patient =
`N_o=2g`

Half life of Barium-131 =
`t_{(1)/(2)}=10 days`

Amount of barium-131 left after 10 days.

t = 10 days

`\lambda =\frac{0.693}{t_{(1)/(2)}}=(0.693)/(10 days)= 0.0693 day^(-1)`

`N=N_o* e^(-\lambda t)`

`\log N=\log N_o -(\lambda t)/(2.303)`

`\log N=\log [2]-(0.0693 day^(-1)* 10 days)/(2.303)`

`N=0.999 g\approx 1 g`

Hence, correct answer is option D.