JIPMER2011PhysicsNuclear Physics
Activity of a radioactive sample decreases to (1/3)rd of its original value in 3 days. Then, in 9 days its activity will become
Options
- A(1 / 27) of the original value
- B(1 / 9) of the original value
- C(1 / 18) of the original value
- D(1 / 3) of the original value
Correct answer
A. (1 / 27) of the original value
Step-by-step solution
R=R₀ e^ - t ( 1 3 )=e^ - 3 =e^ -3 ...(i) Again, R^ R₀ =e^ - 9 =e^ -9 = (e^ -3 )^3= ( 1 3 )^3 [From Eq. (i)] = 1 27 R^ = R₀ 27 Hence, in 9 days activity will become ( 1 27 ) of the original value.