How does distance affect radiation exposure

Interpreting Graphs Some people, such as X-ray technicians, must work near radioactive sources. They know the importance of keeping a safe distance from the source. The graph shows the intensity of a radioactive source versus the distance from the source. 

Note how the intensity of the radiation varies with the distance from the source. The unit of radiation intensity is millirem per second per square meter. (This is the amount of radiation striking a square meter of area each second.) Use the graph to answer the Thinking Critically questions that follow. 

How does the radiation exposure change as the distance doubles from 0.1 meter to 0.2 meter As the distance quadruples from 0.1 meter to 0.4 meter  

State in words the mathematical relationship described in your answer to question 1. 

The maximum radiation exposure intensity that is considered safe is 0.69 mrem/s-m. At what 

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