AP Physics 2 Unit 11 Lab

Elisa Alvarado, Sarah Cratem, Ryan Partain, Julia Reidy

Mr. Thomas

AP Physics 2 cmod

1 May 2016

Unit 11 Lab: Standard Model

Objective: To determine the graphical and mathematical relationship between deflection angle, new wavelength, and electron momentum.

Apparatus:

Procedure:

1. Go to the website http://www.kcvs.ca/site/projects/physics_files/compton-scattering/compton-scattering.swf
2. Start the experiment with a photon angle of 1 degree and a wavelength of 50pm
3. Click the start button to shoot the photon at the electron
4. Record the electron angle, final wavelength, and electron momentum
5. Repeat steps 2-4 with the photon angles 10, 30, 60, 90, 120, 150, and 180

Data:

Final Wavelength vs. Photon Angle

This relationship does not create a straight line; take the cosine of the x-axis (photon angle) to linearize the relationship.

Final Wavelength vs. cos(photon angle)

This relationship is linear.

Electron Momentum vs. Photon Angle

To linearize this relationship, multiply the electron momentum by the cosine of the electron angle, and for the x-axis, take the cosine of the photon angle and divide it by the final wavelength.

Momentum x cos(Electron Angle) vs. cos(Photon Angle) / Final Wavelength

This graph provides a linear relationship.

Conclusion:

The independent variable is the photon angle and the dependent variables are final wavelength, electron angle, and electron momentum.

The first graph shows the relationship between final wavelength and photon angle which is not a straight line. Then by changing the angle from θ to cosθ it becomes linear and can be described using the equation represented in the second graph:

Final wavelength=-24.245pm(cosθ)+524.235pm

The third graph shows the relationship between electron momentum and photon angle. To linearize this graph, for the y-axis multiply the electron momentum by the cosine of the electron angle, and for the x-axis, take the cosine of the photon angle and divide it by the final wavelength. This gives you the linear equation represented in the fourth graph:

(Momentum e-)(Cos(θ2))=(-0.709yN(s)(pm))(1/final wavelength)(cos(θ1) +11.414yN(s)

Errors in this experiment are unlikely because we used a computer simulation to collect our data. However, some mistakes could have possibly been made in rounding errors and calculations.