a sample of radioactive elements contain 4 × 10^10 active nuclei if half life of element is 10 days then the number of decayed nuclei after 30 days is
Answers
Explanation
Number of half- lives
n = t / T1/2 = 30 days / 10 days = 3
[T1/2 = half life period ]
So, number of undecayed radioactive nuclei is given by
N / No = [ 1/2 ]^n
...[ N = Final number, No = Initial number ]
N = No [ 1/2 ]^n = 4 × 10^10 [ 1/2 ]^3
N = 4 × 10^10 × 1/8 = 0.5 ×10^10
Thus, number of nuclei decayed after 30 days
= No - N
= 4 × 10^10 - 0.5 × 10^10
= 3.5 × 10^10
The Number of decayed nuclei after 30 days is 3.5 × 10^10 !
Answer:
Explanation
Number of half- lives
n = t / T1/2 = 30 days / 10 days = 3
[T1/2 = half life period ]
So, number of undecayed radioactive nuclei is given by
N / No = [ 1/2 ]^n
...[ N = Final number, No = Initial number ]
N = No [ 1/2 ]^n = 4 × 10^10 [ 1/2 ]^3
N = 4 × 10^10 × 1/8 = 0.5 ×10^10
Thus, number of nuclei decayed after 30 days
= No - N
= 4 × 10^10 - 0.5 × 10^10
= 3.5 × 10^10
The Number of decayed nuclei after 30 days is 3.5 × 10^10 !