Chapter 1, Question 1.23

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MadisonFuentes1G
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Chapter 1, Question 1.23

Postby MadisonFuentes1G » Tue Oct 10, 2017 5:38 pm

Q 1.23 “The y-ray photons emitted by the nuclear decay of a technetium-99 atom used in radiopharmaceuticals have an energy of 140.511 keV. Calculate the wavelength of these y-rays.”

I‘m not sure how to begin this problem. What measurement is keV exactly, and how do you convert it to joules?

Chem_Mod
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Re: Chapter 1, Question 1.23

Postby Chem_Mod » Tue Oct 10, 2017 9:52 pm

1keV = 1000 ev
1 ev = 1.6*10^-19 Joules. Electron-volts are just different units for energy.

Krupa Prajapati
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Re: Chapter 1, Question 1.23

Postby Krupa Prajapati » Tue Oct 10, 2017 10:01 pm

In addition to converting keV to Joules, another way to start this problem is to use the equation:

wavelength = (hc)/E

h and c are both constants, so we only need to plug in our value for energy for Joules to start the problem. Hope this helps!

Jennie Fox 1D
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Re: Chapter 1, Question 1.23

Postby Jennie Fox 1D » Wed Oct 11, 2017 10:20 am

First, you must convert 140.511 eV to Joules. (1eV = 1.6022 x 10^-19 J).

From there, you use the equation E=hc/lambda and solve for lambda (wavelength).

You should get 8.8237 pm for your answer.


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