1. Tardigrade
  2. Question
  3. Physics
  4. Geiger counter reading of a radioactive sample is initially 6800 counts per minute. The same sample gives a reading of 425 counts per minute 10 h later. The half life of sample is α hours. Find 2 α.

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Q. Geiger counter reading of a radioactive sample is initially $6800$ counts per minute. The same sample gives a reading of $425$ counts per minute $10\, h$ later. The half life of sample is $\alpha$ hours. Find $2 \alpha$.

Nuclei

Solution:

$A=\frac{A_{0}}{2^{n}} \Rightarrow 2^{n}=\frac{6800}{425}$
($n=$ Number of half life)
$2^{n}=16=2^{4}$
$\Rightarrow n=4$
$\Rightarrow 4 \times t_{1 / 2}=10$
$\Rightarrow t_{1 / 2}=2.5\, h$