# Photoelectric Effect - Wavelength of a Photon

## Homework Statement

Calculate the wavelength of a photon having the same momentum as an electron
moving at 1.0  106 m/s.
The answer is supposed to be 0.73 nm.

## Homework Equations

Ek = (m*v^2)/2
Ek = hf - W
p = E/c = hf/c = h/$$\lambda$$

## The Attempt at a Solution

I first found Ek using the kinetic energy formula, using the speed of the electron given in the question and the mass of the electron.
I can't quite figure out where to go next.

## Answers and Replies

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dx
Homework Helper
Gold Member
This problem has nothing to do with the photoelectric effect. Find the momentum of an electron moving at the speed given, substitute it in p = h/λ, and solve for λ.

It is in the photoelectric effect section of the book, though.

Alright, thanks.