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Grade 10Modern Physics

The count rate of a Geiger Muller counter for the radiation of a radioactive material of half-life 30 minutes decreases to 5 sec-1 after 2 hours. The initial count rate was

(a) 20 sec-1

(b) 25 sec-1

(c) 80 sec-1

(d) 625 sec-1

Profile image of Navjyot Kalra
12 Years agoGrade 10
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1 Answer

Profile image of Navjyot Kalra
12 Years ago

(c)

Half-life = 30minutes; Rate of decrease (N) = 5 per second and total time = 2 hours = 120 minutes.

Relation for initial and final count rate

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