Finding the momentum of an electron in terms of a voltage

[la_profesora]

Homework Statement

For a lab we are doing my Modern Physics class, we have fired a beam of electrons at carbon in a glass bulb and observed an interference pattern due to the beam reflecting off of the carbon at the correct angle (when n*wavelength = 2dsin(theta) where d is the distance between atoms of carbon.

We recorded the voltages and the diameter of the circular interference.

Homework Equations

mc^2 = hf and DeBroglie Wavelength:
wavelenth = h/p

The Attempt at a Solution

I tried to use mc^2 = hf but I have no idea where Voltage comes into play.
Any hints are appreciated.

can i just use E = qV, where q is charge of an electron? I'm uncertain...

Gracias,
La Profe

 

[anathema]

Dear La Profe,

Thank you for sharing your lab experiment with us. It sounds like you are on the right track with using the DeBroglie wavelength equation to calculate the wavelength of the electron beam. The voltage does indeed play a role in this experiment.

To understand how voltage comes into play, it may be helpful to review the concept of electron energy levels in an atom. When an electron is accelerated through a potential difference (voltage), it gains energy. This energy can then be used to calculate the momentum of the electron using the equation p = mv, where m is the mass of the electron and v is its velocity.

In your experiment, the electrons are accelerated through a voltage before they hit the carbon atoms. This means that they have a specific energy and momentum when they interact with the carbon atoms. The DeBroglie wavelength equation takes into account the momentum of the electron, so by using the voltage to calculate the momentum, you can then use the DeBroglie equation to find the wavelength.

I hope this helps. Good luck with your experiment!