- #1
Brendanphys
- 11
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Homework Statement
This is a problem I did during a test, and I am looking it over to see what I did wrong..
1. An Electron is accelerated by a potential difference of 75V. What is the de Broglie wavelength
Homework Equations
P = h/λ
Ek = 1/2mv^2
eV = 1.6E-19
The Attempt at a Solution
P = h/λ
λ = h/p (1)
Ek = 1/2mv^2
(2Ek/m)^1/2 (2)
Sub (1) into (2)
λ = h/p
λ = h/m((2Ek/m)^1/2)
I figured 75V = 75*eV = 75*(1.6E-19) = 1.2E-17J
So 1.2E-17J = Ek
I Plugged in all the known values into
λ = h/m((2Ek/m)^1/2)
and got the answer as: 1.4E21
Any clues as to what I did wrong? I assume it has something to do with my volt conversion, any help would be greatly appreciated.