Question

1. Radio active substances x and y contain equal number of atoms initially. Half life of x and y are 1 day and 2 days respectively. At the end of 2nd day and the ratio of rate of disintegration of x and y is. A) 1 : 2 b) 2 :1 c) 1:1 d) 1:4

Answer 1

Answer A) 1:2 is right

Answer 2

Hey dear,

● Answer -
Rx : Ry = 1 : 1 .

● Explanation -
# Given -
Let tx & ty be half lives.
tx = 1 day
ty = 2 days

# Solution -
Let N be radioactive sample of each X & Y initially.

After two days,
Nx = (1/2)^(T/tx) = (1/2)^2 = N/4
Ny = (1/2)^(T/ty) =(1/2)^1 = N/2

Ratio of decay rate is given by -
Rx / Ry = Ty.Nx / Tx.Ny
Rx / Ry = (2 × N/4) / (1 × 1/2)
Rx / Ry = 1

Therefore, Rx : Ry = 1 : 1 .

Hope this helps you..