(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Find the energy (in joules), rest mass (kg), speed (m/s), wavelength (m), and momentum (kgm/s) of a 2.2 eV electron.

I'm having trouble finding the speed of the electron; once I have that I can find the wavelength and momentum.

E= energy

p= momentum

h= Planck's constant (6.63 x 10^{-34}Js)

c= the speed of light (3.0 x 10^{8}m/s)

λ = wavelength

2. Relevant equations

1 eV = 1.60 x 10^{-19}J

E_{total}=E_{k}+E_{rest}

E = hc/λ

p = h/λ

3. The attempt at a solution

Energy of electron in joules:

2.2 eV = 3.52 x 10^{-19}J

Rest mass of an electron:

9.11 x 10^{-31}kg

****(Is this a correct answer or do I need to calculate rest mass?)

Speed of electron:

I tried this equation:

E_{total}=E_{k}+E_{rest}

E_{k}=E_{total}-E_{rest}

but it doesn't work because the total energy given for the electron is less than the rest energy calculated...

I'm not sure what equation other equation I can use. Also, I don't know if relativity must be taken into account if the electron's speed is close to the speed of light?

Thank you!

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# Homework Help: Quantum Mechanics: Speed of an electron

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