Radioactive Decay: the Half-Life of Cobalt-60 Is 5

question 58

Multiple Choice

Radioactive decay: The half-life of cobalt-60 is 5.3 years, while that of strontium-90 is 28 years. Suppose you have a sample of each, such that they initially contain equal numbers of atoms of these nuclides. How will the activities (number of decays per second) of the samples compare?

• A) The activity of the cobalt-60 sample will be greater.
• B) The activities cannot be compared without more information.
• C) The activities will be equal.
• D) The activity of the strontium-90 sample will be greater.

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