CGPET 2021 Solved Paper

Let weight of A and B be xg.
Half-life of A is 1‌min that means it take 1min for compound A to be half of its initial amount.
∴ Weight of A after 1‌min=

x

2

g
After 2‌min, it will be =

x

4

g
and similarly after 4‌min, weight of A will be

x

16

g
Also, half-life of B is 2‌min that means, it take 2 min for compound B to be half of its initial amount.
∴ Weight of B after 2‌min=

x

2

g
∴ Weight of B after 4‌min=

x

4

g
∴ Ratio of compound A and B disintegrated will be
=

Weight‌of‌compound‌A

weight‌of‌compound‌B

=

x

16

÷

x

4

=

x

16

×

4

x

=

1

4

∴ Ratio will be 1:4.