Difference between revisions of "Solutions 3"
From mn/safe/nukwik
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All <sup>99m</sup>Tc has disintegrated and turned into <sup>99</sup>Tc. The number of <sup>99</sup>Tc atoms will therfore be the same as the original number of <sup>99m</sup>Tc atoms. | All <sup>99m</sup>Tc has disintegrated and turned into <sup>99</sup>Tc. The number of <sup>99</sup>Tc atoms will therfore be the same as the original number of <sup>99m</sup>Tc atoms. | ||
− | <math>N=\frac{D}{\lambda} \rightarrow \frac{4\cdot 10^{7}Bq}{3.21\cdot 10^{-5}s^{-1}}=1.25\cdot 10^{12}atoms</math> | + | <math>N=\frac{D}{\lambda} \rightarrow \frac{4\cdot 10^{7}Bq}{3.21\cdot 10^{-5}s^{-1}}=1.25\cdot 10^{12}atoms</math> |
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+ | <br> | ||
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+ | '''6:'''<br><br> | ||
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+ | #1 g natural Lu contains 0.0259 g <sup>176</sup>Lu, with a half-life equal to 3.8 • 10<sup>10</sup> år. This gives D = 51 Bq <br> | ||
+ | #There are two naturally occuring radioisotopes of Sm, <sup>147</sup>Sm and <sup>148</sup>Sm, which gives D = 127.24 Bq + 0.001 Bq = 127 Bq. | ||
+ | <br> | ||
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+ | '''7: '''3002 kg | ||
+ | <br> | ||
+ | |||
+ | '''8:''' <br> | ||
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+ | #18.5 kg | ||
+ | # After 2.455 • 10<sup>5</sup> years it will be 2.299 • 10<sup>8</sup> Bq <sup>238</sup>U left, which is equal to 18.49 kg.<br><br> | ||
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+ | <br> |
Revision as of 10:57, 19 June 2012
Amount of radioactive material (number of nuclei <-> number of moles <-> weigth) and law of radioactive decay
1:
- 3.2 • 108 Bq
- 383 Bq
- 2.3 • 109 Bq
- 8 • 104 Bq
2:
- 1.78 • 1013 atoms.
- 2 • 1011 atoms.
3: 2.40 g 60Co.
4:
- 2.53 • 105 Bq.
- 7.19 years = 7 years and 68 days.
5: The mass of 99mTc is 20.5 ng. After one week 28 half-times will have past, and the activity will be the following:
D = D0 • (½)28 = 4 • 107 Bq • (½)28 = 0.15 Bq.
All 99mTc has disintegrated and turned into 99Tc. The number of 99Tc atoms will therfore be the same as the original number of 99mTc atoms.
6:
- 1 g natural Lu contains 0.0259 g 176Lu, with a half-life equal to 3.8 • 1010 år. This gives D = 51 Bq
- There are two naturally occuring radioisotopes of Sm, 147Sm and 148Sm, which gives D = 127.24 Bq + 0.001 Bq = 127 Bq.
7: 3002 kg
8:
- 18.5 kg
- After 2.455 • 105 years it will be 2.299 • 108 Bq 238U left, which is equal to 18.49 kg.