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QNEET-2018-Ph-905: NEET 2018 Physics - Class 12 NEET-2018-Ph-905 Solution: For a radioactive material half-life is 10 minutes. If…
For a radioactive material half-life is 10 minutes. If initially there are 600 number of nuclei the time taken (in minutes) for the disintegration of 450 nuclei is 20 10 30 15
Multiple Choice Options
- A 20
- B 10
- C 30
- D 15
Step-by-Step Verified Solution
Given N 0 = 600, N 1 = 450, T = 10 min
Number of nuclei remaining, N = 600 � 450
= 150 after time �t�
N N 0 = 150 600 = 1 4
According to the law of radioactive decay,
N = N 0 e - _ t
N N 0 = ( 1 2 ) t T 1 / 2
_ 150 600 = ( 1 2 ) t T 1 / 2
_ ( 1 2 ) 2 = ( 1 2 ) t T 1 / 2
_ t = 2T 1/2 = 2 _ 10 minutes = 20 minutes