The half life of radon is 3.8 days. After how many days will only one ...
Let the initial amount of radon be N
0 and the amount left after t days be N which is equal to N
0/2
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The half life of radon is 3.8 days. After how many days will only one ...
Given: Half-life of radon = 3.8 days
To find: After how many days will only one twentieth of a radon sample be left over?
Let's first understand what is meant by half-life. Half-life is the time taken for half of the radioactive substance to decay. It is denoted by the symbol 't1/2'.
We are given the half-life of radon as 3.8 days. This means that after every 3.8 days, the amount of radon reduces to half of its original amount.
Now, we need to find the time taken for the radon sample to reduce to one twentieth of its original amount.
Let's assume that the original amount of radon is 'x'.
After the first 3.8 days, the amount of radon left will be x/2.
After the second 3.8 days (total of 7.6 days), the amount of radon left will be (x/2)/2 = x/4.
Similarly, after the third 3.8 days (total of 11.4 days), the amount of radon left will be (x/4)/2 = x/8.
We can continue this process, and after n half-lives, the amount of radon left will be (x/2^n).
We need to find the value of n such that (x/2^n) = (1/20)x.
Solving for n, we get n = 4.16.
Therefore, the time taken for the radon sample to reduce to one twentieth of its original amount is 4.16 x 3.8 = 15.808 days, which can be approximated to 16.45 days.
Hence, the correct answer is option D.
The half life of radon is 3.8 days. After how many days will only one ...