## Homework Problem 1.23

$c=\lambda v$

Lauren Hekman 1A
Posts: 38
Joined: Fri Sep 25, 2015 3:00 am

### Homework Problem 1.23

The problem asks: "The gamma 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 gamma rays."

What is the unit keV? How do I convert this unit to joules?

Lauren Doh 3E
Posts: 13
Joined: Fri Sep 25, 2015 3:00 am

### Re: Homework Problem 1.23

1 keV is equal to 1000 eV, and 1 eV is equal to 1.602x10^-19 Joules. So if you had 140.511 keV, you'd multiply it by 1000 eV / 1 keV. Then you'd multiply that by 1.602x10^-19 J / 1 eV.

Brooke Tobias 1B
Posts: 13
Joined: Fri Sep 25, 2015 3:00 am

### Re: Homework Problem 1.23

Basically, an eV is the amount of energy transferred by an electron moved across an electric potential difference of one volt. This amount was derived from multiplying one volt (J/C) by the charge of a single electron (C), giving us 1.60218 x 10^-19 J.