NTA Abhyas JEE Main2020PhysicsNuclear PhysicsPractice
What is the disintegration constant of radon if the number of its atoms diminishes by 18 % in 24 h ? [Take ln 0 . 82 ≈ - 0 . 2 ]
Options
- A2.3 × 10 - 3 s - 1
- B2.3 × 10 - 4 s - 1
- C2.3 × 10 - 5 s - 1
- D2.3 × 10 - 6 s - 1
Correct answer
D. 2.3 × 10 - 6 s - 1
Step-by-step solution
Undisintegrated part N N 0 = ( 100 - 18 ) % = 82 % Using relation N = N 0 ( e - λt ) 82 100 = e - 24 × 60 × 60 λ ∴ 24 × 60 × 60 × λ = log 100 82 or λ = 2 .3 × 10 - 6 s - 1