Question

Copy and complete the following table for a radioactive element whose half-life is 10 minutes. Assume that you have 30g of this element at t = 0.

 

Answer 1

`∵  N = (N_0)/2^n` , n  being no. of half-life spent.

t = 20 min means 2 half-life and t = 30 min means 3 half-life

`therefore N_20min = N_0/2^2 = N_0/4 and N_30min = N_0/2^3 = N_0/8`

`therefore m_20min = m_0/4 = (30  gm)/4 = 7.5  gm`

and `m_30min = m_0/9 = (30 gm)/9 = 3.33 gm`