question_answer

If \[8\times {{10}^{10}}\] atoms of Radon are separated from Radium, how many disintegrations will occur in \[11.46\]days?

A) \[8\times {{10}^{10}}\]           

B) \[8\times {{10}^{6}}\]

C) \[7\times {{10}^{10}}\]           

D) \[7\times {{10}^{9}}\]

Correct Answer: C

Solution :

As, 11.46 days is three times the half-life of Radon. So, decay scheme is as follows 3.82 days.

So, only \[1\times {{10}^{10}}\]active nuclii remains after 3-half lives.

So, \[7\times {{10}^{10}}\]disintegrations would occur in 11.46 days.