Question

A freshly isolated sample of 90Y was found to have an activity of 2.2 × 105 disintegrations per minute at 1:00 p.m. on December 3, 2006. At 2:15 p.m. on December 17, 2006, its activity was measured again and found to be 5.8 × 103 disintegrations per minute. Calculate the half-life of 90Y.

Answer 1

To calculate the half-life of 90Y, use the formula t1/2 = (t2 - t1) / (ln(N1/N2)). Plug in the given values to find the half-life.

Step-by-step explanation:

To calculate the half-life of 90Y, we can use the formula:

t1/2 = (t2 - t1) / (ln(N1/N2))

Where t1/2 is the half-life, t1 and t2 are the times at which the activities are measured, N1 is the initial activity, and N2 is the final activity.

In this case, t1 = 1:00 p.m. on December 3, 2006, and N1 = 2.2 × 105 disintegrations per minute. t2 = 2:15 p.m. on December 17, 2006, and N2 = 5.8 × 103 disintegrations per minute.

Plugging these values into the formula, we get:

t1/2 = (2:15 p.m. on December 17, 2006 - 1:00 p.m. on December 3, 2006) / (ln(2.2 × 105/5.8 × 103))