Author Question: The material used in certain nuclear bombs is 239Pu, which has a half-life of about 20,000 years. ... (Read 70 times)

123654777 · **on:** Jul 29, 2018

The material used in certain nuclear bombs is 239Pu, which has a half-life of about 20,000 years. How long must we wait for a buried stockpile of this substance to decay to 4.0 of its original 239Pu mass?

A) 93,000 y
B) 64,000 y
C) 45,000 y
D) 800 y

Question 2

What mass of 14C (having a half-life of 5730 years) do you need to provide a decay rate of 280.0 Bq? (1 u = 1.6605 10-27 kg)

A) 1.70 10-12 kg
B) 5.38 10-19 kg
C) 3.84 10-20 kg
D) 8.68 10-13 kg