## 1B.15

Aliya Jain 2B
Posts: 80
Joined: Wed Sep 11, 2019 12:16 am

### 1B.15

"The g-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 g-rays" What is the unit keV?

lilymayek_1E
Posts: 84
Joined: Sat Aug 17, 2019 12:16 am

### Re: 1B.15

the unit keV is a kiloelectron volt, where an electronvolt is the KE gained/lost by a single electron (which would correlate with the photons in the question).
the electronvolt is the standard unit, so a kiloelectronvolt is equal to 1000 electronvolts.
**an electron has energy equal to 1.6022x10^-19 joules, and an electronvolt is equal to this number of joules**
so, 1 eV = 1.6022x10^-19 J (E of an electron)
1000 eV = 1 keV
hope this helps!

Jessica Booth 2F
Posts: 76
Joined: Fri Aug 30, 2019 12:18 am

### Re: 1B.15

keV is kilo-electron volts, which is a unit for energy. The conversion from kilo- electron volts to electron volts is (1000 eV/keV) and then the conversion from eV to J is $\left ( 1.602 * 10^{-19} \right )$ J/ 1eV.