The decay of a radioactive material is monitored using a Geiger counter. At the start, the count rate is 2000 decays/minute. Four hours later the decay rate is 500 counts/min. What is the half-life of the material?

The half-life of the material is 2 years

Explanation:

Given;

initial count rate = 2000 decays/minute

final count rate =  500 counts/min

decay time = Four hours

To determine the half life of the material; we create a simple decay table that matches the decay time and count rates.

time (years)                     count rate

0                                    2000 decays/minute

2                                     1000 decays/minute

4                                     500 decays/minute

Half life is the time intervals = 2 years

Also using a formula;

Therefore, the half-life of the material is 2 years

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