The half-life of I 131 is 8 days. Given a sample of I 131 at time t = 0, we can assert that

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Wave Optics

Question

The half-life of I¹³¹ is 8 days. Given a sample of I¹³¹ at time t = 0, we can assert that
no nucleus will decay before t = 4 days
no nucleus will decay before t = 8 days
all nuclei will decay before t = 16 days
a given nucleus may decay after t = 0

Solution

a given nucleus may decay after t = 0