Share
Explore BrainMass

Radioactive Decay Concept Questions

13. Which one of the following can be done to shorten the half life of the radioactive decay of uranium-238?

a. Oxidize it to the +2 oxidation state.
b. Heat it.
c. Freeze it.
d. Convert it to UF6.
e. None of these

14. The half-life for beta decay of strontium-90 is 28.8 years. A milk sample is found to contain 10.3 ppm strontium-90. How many years would pass before the strontium-90 concentration would drop to 1.0 ppm?

a. 131
b. 0.112
c. 92.3
d. 186
e. 96.9

15. The decay of a radionuclide with a half-life of 4.3 x 105 years has a rate constant (in yr-1) equal to ________.

a. 6.2 x 105
b. 5.9 x 10-8
c. 2.8 x 103
d. 2.3 x 10-6
e. 1.6 x 10-6

16. Consider the following data for a particular radionuclide:
Time Nt
0 min 1.23 g
3 1.15
6 1.08
9 1.01
12 0.940

What is the half-life (in min) of this radionuclide?

a. 30.9
b. 0.0242
c. 0.0224
d. 0.0324
e. 44.64

17. The mass of a proton is 1.673 x 10-24 g. The mass of a neutron is 1.675 x 10-24 g. The mass of the nucleus of an 56Fe atom is 9.289 x 10-23 g. What is the nuclear binding energy (in J) for Fe56?

(C = 3.00 x 108 m/s)

a. 7.72 x 10-8
b. 7.72 x 10-11
c. 6.07 x 106
d. 2.57 x 10-16
e. 8.36 x 10-9

Solution Preview

13. Which one of the following can be done to shorten the half life of the radioactive decay of uranium-238?

e. None of these

________________________________

14. The half-life for beta decay of strontium-90 is 28.8 years. A milk sample is found to contain 10.3 ppm strontium-90. How many years would pass before the strontium-90 concentration would drop to 1.0 ppm?

log (co/ct) = kt/2.303
where co is the initial amount and ct is the amount remaining at time t.

But first, we have to calculate k, the rate ...

Solution Summary

This solution contains explanations and calculations to determine the right answer for the radioactive decay questions.

$2.19