Given, half life T1/2=2.2×109 s Rate of disintegration, R=1010 s−1 If N be the number of nuclei present, then the rate of disintegration is dtdN=λN(λ= decay constant )⇒R=λN or N=λR… (i) Also, the half life is given by, T1/2=λ0.693⇒λ= T1/20.693 From Eq. (i) and (ii), we get N=0.693R×T1/2=0.6931010×2.2×109=3.17×1019
The rate of radioactive disintegration at an instant for a radioactive sample of half life 2.2 × 10^9 ~s is 10^10 ~s^-1. The number of radioactive…
NEET UG 2019 — Physics Modern Physics
2019mcqmedium
The rate of radioactive disintegration at an instant for a radioactive sample of half life 2.2×109 s is 1010 s−1. The number of radioactive atoms in that sample at that instant is
Official previous-year question
Held on 30 Apr 2019 · Verified 9 Jul 2026.
Options
- A
3.17×1020
- B
3.17×1017
- C
3.17×1018
- D
3.17×1019
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