Starting with a sample of pure ⁶⁶Cu, 7/8 of it decays into Zn in 15 minutes. The corresponding half-life is:

Question

Quizplus · Accepted Answer

Half-life (t1/2) is the time taken for half of the sample to decay. Given that 7/8 of the sample decays, we can calculate the fraction remaining as 1/8.

1/2 = (7/8)^n

Where n is the number of half-life intervals that have passed.

Solving for n, we get:

n = log(1/2) / log(7/8)

n ≈ 0.4306

The time taken for 0.5 fraction to decay is given by:

t1/2 = n * 15 minutes

t1/2 ≈ 6.459 minutes

Therefore, the closest answer choice is B) 5 minutes.

Starting with a Sample of Pure 66Cu, 7/8 of It

Starting with a Sample of Pure ⁶⁶Cu, 7/8 of It