Cobalt-60 is commonly used as a source of radiation for the prevention of food spoilage. Bombarding cobalt-59 nuclei with neutrons produces the nuclide cobalt-60. A food irradiation facility replaces the cobalt-60, a source of gamma rays, when the radioactivity level falls to 1/8 of its initial level. The nuclide cesium-137 is also a source of radiation for the prevention of food spoilage.
68 Identify one emission spontaneously released by a cobalt-60 nucleus. [1]
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69 Determine the total number of years that elapse before an original cobalt-60 source in an irradiation facility must be replaced. [1]
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15.78y 1-->1/2-->1/4-->1/8, so 3 half lives 3 x 5.26y |
70 Complete the nuclear equation in your answer booklet for the decay of cesium-137. Your response must include the symbol, atomic number, and mass number of the missing particle. [1]
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