NTA Abhyas JEE Main2020PhysicsNuclear PhysicsPractice
The fraction of atoms of a radioactive element that decays in 6 days is 7 8 . The fraction that decays in 10 days will be
Options
- A77 80
- B71 80
- C31 32
- D15 16
Correct answer
C. 31 32
Step-by-step solution
7 8 fraction decays in 6   days 1 8 fraction is active after 6   days   By using, N = N 0 1 2   t / T 1 / 2 N = N 0 2 n N 0 8 = N 0 2 n n = 3 6   days   =     half   lives t 1 2 = 2   days 10   days = 5   t 1 / 2 N = N 0 2 5 = N 0 32 So   decay = N 0 - N 0 32 = 31 32 N 0