## HW chapter 1 problem 23 [ENDORSED]

$E=hv$

Angela_Kim_1N
Posts: 21
Joined: Fri Jul 22, 2016 3:00 am

### HW chapter 1 problem 23

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

The solution manual says that in order to convert eV to Joules we have to multiply the eV by 1.6022*10^-19.
I was wondering if this is a constant that we have to memorize or where this number came from.
Thanks!

Theresa_Trieu_2G
Posts: 21
Joined: Wed Sep 21, 2016 2:57 pm

### Re: HW chapter 1 problem 23  [ENDORSED]

1 eV = 1.602 x 10^-19 J. I don't think we have to memorize this; it's given on the formula sheet on the back of the periodic table we got.

Audrey Magsig 1E
Posts: 17
Joined: Wed Sep 21, 2016 3:00 pm

### Re: HW chapter 1 problem 23

We talked about this in my discussion lecture today! Our TA said that we will be given the value for the conversion as well as values like the masses of protons, electrons, and neutrons.

Hope this helps!