NEET2008PhysicsNuclear PhysicsActual
Two radioactive materials X₁ and X₂ have decay constants 5 and respectively. If initially they have the same number of nuclei, then the ratio of the number of nuclei of X₁ to that of X₂ will be 1 e after a time
Options
- A1 2
- B1 4
- Ce
Correct answer
C. e
Step-by-step solution
If N is the number of radioactive nuclei present at some instant, then N=N₀ e^ - t The constant N₀ represents the number of radioactive nuclei at t=0 Now, aligned & N₁ N₂ = e^ - ₁ t e^ - ₂ t & N₁ N₂ = e^ -5 t e^ - t =e^ -4 t & N₁ N₂ = 1 e aligned but N₁ N₂ = 1 e (as provided) Therefore, 1 e = 1 e^ 4 t or 4 t=1 or t= 1 4