A radioactive substance of half-life 6 min is placed near a Geiger counter which is found to resister 1024 particles per minute. How many particles per minute will it register after 42 min?

Question

Dr. Abubacker · Accepted Answer

(b) $n = \frac{t}{T} = \frac{42}{6} = 7$
$\frac{N}{N_{0}} = \left( \frac{1}{2} ight)^{n} = \left( \frac{1}{2} ight)^{7} = \frac{1}{128}$
As rate of disintegration$\  \propto \ N$,
$	herefore\ \frac{R}{R_{0}} = \frac{1}{128};R = \frac{R_{0}}{128} = \frac{1024}{128} = 8{\min^{\ }}^{- 1}\ $

Q. A radioactive substance of half-life 6 min is placed near a Geiger counter which is found to resister 1024 particles per minute. How many particles per minute will it register after 42 min?

Explanation

Reviewed by Dr. Abubacker

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