NEET Physics Nuclei Questions Solved

NEET - 2011

Two radioactive nuclei P and Q, in a given sample decay into a stable nucleous R. At time t=0, number of P species are 4N0 and that of Q are N0 and that of Q are N0.Half -life of P(for conversion to R) is 1 min where as that of Q is 2 min. Initially there are no nuclei of R present in the sample. When number of nuclei of P and Q are equal, the number of nuclei of R present in the sample would be 

(a)3N0                                          (b)9N02

(c)5N02                                       (d)2N0

Initially P4N0

          QN0

Half life TP1 min

           TQ2min

Let after time t number of nuclei of P and Q are equal i.e,4N021/1=N021/2

4=21/2

22=21/2

t2=2

t=4min

Disactive nucleus or Nuclei of R

=4N0-4N024+N0-N022

=4N0-N04+N0-N04

=5N0-N02=92N0

 

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