Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

1. What is the half-life associated with each of the following decay constants?

ID: 1457677 • Letter: 1

Question

1. What is the half-life associated with each of the following decay constants? (a) 0.523/day; (b) 0.035/second; (c) 1.25/minute.

B) What is the decay constant associated with each of the following half-lives? (a) 8.20 days; (b) 3.4 x 10-3 second; (c) 2.2 minutes.

C) Barium-137m has a half-life of 2.50 minutes. - If a sample of Barium-137m has an initial activity of 2.00 microCuries, what is the activity at… (a) t = 1.00 minute? (b) 2.00 minutes? (c) 8.00 minutes? (d) 15.0 minutes?

D) The decay constant of a radioactive source is 0.150/second. The initial mass of the source is 4.2 micrograms. - What is the mass of the source at t = (a) 0.200 second? (b) 4.80 seconds? (c) 10.0 seconds? (d) 12.0 seconds.

Explanation / Answer

1)

for given decay constant

half life = ln(2)/decay constant

a) decay constant = 0.523 /day

half life = ln(2)/0.523 day

half life = 1.33 days

b)
decay constant = 0.035/second

half life = ln(2)/0.035/second

half life = 19.8 seocnds

c)

decay constant = 01.25 /minute

half life = ln(2)/1.25 /minute

half life = 0.55 minute

2)

now , decay constant = ln(2)/half life

decay constant = ln(2)/8.20 days

decay constant = 0.0845/day