KEAM 2015 Physics and Chemistry Paper

Given, half- life of species
A=4 days
Half- life of species B=8 days
For species A,N=N0(‌

1

2

)n;n=‌

16

4

=4
Now, ‌‌N1=N0(‌

1

2

)4....(i)
Similarly, for species B
N2=N0(‌

1

2

)2̣...(ii)
On dividing Eq. (i) from Eq. (ii), we get
‌

N1

N2

=‌

(2)2

(2)4

⇒‌

N1

N2

=‌

1

4

⇒‌‌N1:N2=1:4