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A 300-day old radioactive substance shows an activity of 5000 dps, 150 days later its activity becomes 2500 dps. What was its initial activity?

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in Physics – Class 12 by (135k points)
A 300-day old radioactive substance shows an activity of 5000 dps, 150 days later its activity becomes 2500 dps. What was its initial activity?

(a) 25000 dps

(b) 20000 dps

(c) 32000 dps

(d) 5000 dps

I got this question in an international level competition.

I want to ask this question from Nucleus in portion Nucleus of Physics – Class 12

1 Answer

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Best answer
Right option is (b) 20000 dps

Easy explanation: The expression is given as:

R0 = 4R

4R = 4 × 5000

R0 = 20000dps.

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