Question

7. Define the term 'decay constant of a radioactive sample. The rate of disintegration of a
given radioactive nucleus is 10000 disintegrations/s and 5,000 disintegrations/s after 20 hr
and 30 hr respectively from start. Calculate the half life and initial number of nuclei at t=0
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Answer 1

Answer:

Radioactive constant of a fsubtance may be difined as the reciprocal of the time, after which the number of atoms of a radioactive sbstance decreases to 0.368 (or 36.8%) of their number of atoms preent initially.

R=R0e−λt

10000=R0e−λ(20) ...(1)

5000=R0e−λ(30) ...(2)

dividing equation no. (1) by (2)

2=e−λ(−10)

⇒ λ=0.0693hr−1

Half life T1/2=0.693λ=0.6930.0693=10 years

R=λN0e−λt

N0=Rλe−λt

N0=10,0000.0693×e−0.0693×20

N0=577200.57=577200 atoms.

Explanation:

Answer 2

Answer:https://goprep.co/define-the-term-decay-constant-of-a-radioactive-sample-the-i-1nlsqe

Explanation: