Answer:
Step-by-step explanation:
A) The half-life of a certain isotope is 1 day. At the end of 3 days, how much of the isotope remains?
1/16 ,
1/8,
none of it ,
1/3,
none above.
Answer:
1/8
Step-by-step explanation:
Given data:
Half life of isotope = 1 day
At the end of day remaining amount = ?
Solution:
Consider that original amount of isotope is 100%.
At time zero = 100%
At one day = 100/2 = 50%
At second day = 50/2 = 25%
At third day = 12.5%
It is the 1/8 of 100.
Multiply the 12.5% × 8 = 100%
It means at the end of 3rd day 1/8 of original amount will remain.
B) The half-life of a certain isotope is 30 seconds. How much of a 200 g sample will remain after 2 minutes?
50 , 6.25 , 170, 12.5 , 100
Answer:
12.5 g
Step-by-step explanation:
Given data:
Half life = 30 sec
Total amount = 200 g
Amount after 2 min (120 sec) = ?
Solution:
Half lives = T elapsed / half life
Half lives = 120 sec/ 30 sec
Half lives = 4
At time zero = 200 g
At first half life = 200 g /2 = 100 g
At second half life = 100 g/2 = 50 g
At third half life = 50 g/2 = 25 g
At 4th half life = 25 g/2 = 12.5 g