Nuclear & Particle Physics - Radioactive

An experimenter measures 9924 counts during one hour from a radioactive sample. From this number the counting rate of the sample can be estimated with a standard deviation of most nearly 

A. 100
B. 200
C. 300
D. 400
E. 500
(GR8677 #40)
Solution:

Radioactive decay can be described by Poisson Distribution.

Poisson Distribution (PD):
Probability distribution of discrete events over an interval (time. distance, etc)

In PD, Standard Deviation, σ μ (see Notes)
μ = expected number of events

Given: μ 9924 ≈ 10000
σ √10000 = 100

Answer: A


Notes: (click to enlarge)




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