Half-lives of two radioactive nuclei A and B are 10 minutes and 20 minutes, respectively. If, initially a sample has an equal number of nuclei, then after 60 minutes, the ratio of decayed numbers of nuclei A and B will be:
3 : 8
1 : 8
8 : 1
9 : 8
Number of nuclei in terms of half life -
- wherein
Very useful to determine number of nuclei in terms of half life
A | B | |
10 m | 20 m | |
t | 60 m | 60 m |
=6 |
=3 |
after 60 minutes.
undecay
undecay
So,
Option 1)
3 : 8
Option 2)
1 : 8
Option 3)
8 : 1
Option 4)
9 : 8
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