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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.

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