1. A nuclear power plant worker needs to get as close to a radiation source as possible. She is not allowed to occupy a space where the count rate is greater than 10,000 counts per minute above background. If her Geiger counter detects 3000 counts per minute above background at a distance of 20 meters, what is her minimum safe distance from the source?

 

 
 
 
 
 
 
 
 

2. A man with a Geiger counter gets a reading of 1000 counts per minute above background when he is 0.5 meters away from a gamma source. What reading should he expect to get if he a) doubles his distance from the source, b) triples his distance from the source, c) halves his distance from the source?

 

 
 
 
 
 
 
 
 
 

3. Simple Simon is holding a radioactive source at arm's length (about 1.0 meter). Prudent Patty is a safe 20 meters away where she detects 300 counts per minute above background with her trusty Geiger counter. Calculate the counts above background that Patty would detect if she took a reading near Simon's chest.

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