AP Physics 2 Unit 10 Lab

Elisa Alvarado, Sarah Cratem, Ryan Partain, Julia Reidy

Mr. Thomas

AP Physics 2 cmod

14 March 2016

Unit 10: Quantum Model Lab Report

Objective: To determine the relationship between brightness and density of light related to the current it produces.

Apparatus:

Procedure:

Finding the Relationship Between Current and Photon Density
1. Choose Sodium as the target metal
2. Set the voltage to a constant 1 V
3. Set the wavelength to 250 nm
4. Set the photon density = 0.01
5. Hit “Record Data Point”
6. Change the photon density by adding 0.10. Hit “Record Data Point”
7. Repeat step 6 for (0.10,1.00]; you should have 11 data points

Finding the Relationship between Current and a Change in Potential
1. Using Sodium, set the photon density = 1
2. Set the wavelength at 250 nm
3. Set the voltage = 0 V
4. Hit “Record Data Point”
5. Change the voltage by adding 0.500V. Hit “Record Data Point”
6. Repeat Step 5 for (0.500V, 5.000V]; you should have 11 data points

Finding the Relationship between Maximum Kinetic Energy and Frequency
1. Using Sodium, set the photon density = 1, and set the voltage = 1 V
2. Start with wavelength = 800 nm; this will result in a frequency of 3.75 x1014Hz
3. Hit “Record Data Point”
4. Subtract 86 nm from the wavelength to increase the frequency. Hit “Record Data Point”
5. Repeat Step 4 for [200 nm, 700 nm)
6. Calculate by using a spreadsheet software and the equation 𝜙 (multiply Plank’s constant, eV·s, by the frequency column and subtract the work function for Sodium which equals 2.28eV)

Data Table:

Graphs:

Energy vs. Frequency

Conclusion:

In the first trial the independent variable was photon density and the dependent variable was current. In the second trial the independent variable was voltage and dependent was current. In the third trial the independent variable was wavelength/frequency and the dependent was Kinetic Energy, which was solved for using the equation UK = (4.063 x 10-15eVs)(f) - 2.828eV, where Planck's constant is equal to the slope. The x intercept shows the minimum amount of frequency needed to expel an electron from the Sodium. The y intercept shows us how much force is needed to eject an electron from the Sodium. The generalized equation we can derive from this data is E= hf - ϕ. The slope (h) represents Planck's constant.  The equation E= hf - ϕ shows that kinetic energy of the photoelectron is equal to Planck's constant (h) multiplied by the light’s frequency minus the y intercept (ϕ). The errors that could have happened during our experiment are limited because we used a computer to compute the data used in our analysis. The only way for error to be possible is if we rounded numbers wrong or if we accidentally plugged numbers wrong into our calculator.

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.

AP Physics 2 Unit 9 Lab

Elisa Alvarado, Sarah Cratem, Ryan Partain, Julia Reidy

Mr. Thomas

AP Physics 2 cmod

1 March 2016

Unit 9: Light Wave Model Lab Report

Objective: To determine the effect of object distance on image distance and height for both red and blue lights.

Apparatus:

Procedure:

1. Set up the blue light in a fixed position on the magnetic board.
2. Place the object 16.5 cm away from the light, and use a marker board to view the image, moving it toward or away from the light as necessary to view the focused image.
3. Record the image distance (distance to the marker board from the light) and image height.
4. Repeat steps 2-3 for object distances of 21 cm, 23 cm, 25 cm, 27 cm, 29 cm, 31 cm, and 39.5 cm.
5. Set up the red light in a fixed position on the magnetic board.
6. Place the object 16.6 cm away from the light, and use a marker board to view the image, moving it toward or away from the light as necessary to view the focused image.
7. Record the image distance (distance to the marker board from the light) and image height.
8. Repeat steps 6-7 for object distances of 17.1 cm, 18.4 cm, 20.3 cm, 22.3 cm, 24.3 cm, 27.2 cm, and 38.6 cm.

Data:

Blue Light:

Image Distance vs. Object Distance

This thth

Th

1/ Image Distance vs. 1/ Object Distance

1/di=-0.954(1/do)+0.059cm

-Image Height/ Object Height vs. Image Distance/ Object Distance

-Hi/ho=0.892(di/do)

Red Light:

Image Distance vs. Object Distance

1/ Image Distance vs. 1/ Object Distance

1/di=-1.106(1/do)+0.066

-Image Height/ Object Height vs. Image Distance/ Object Distance

-Hi/ho=0.968(di/do)

Conclusion: The relationship between the two variables, the image distance and the object distance, was hyperbolic. Some constants in the experiment were the lights used. For example the same exact blue light and same exact red light was used throughout the experiment. The lights were also kept at a fixed position on the magnetic board. The material the light traveled through was constant throughout the experiment as well. The equation we got from our data showed that as di/do increased, hi/ho also increased proportionally. The equation from this data is hi/ho=0.968(di/do). To generalize this even more, you can see that (image height/object height)=0.968(image distance/object distance). The slope that we attained was slightly off because we could not maintain a perfect experiment since the slope was supposed to be a value of 1. Therefore, the general equation we derived from our data was hi/ho=di/do(1)=M. Since the value of the slopes were all around 1, another equation that shows the relationship between focal length (F), object distance (do), and image distance (di). This equation can be generalized to show that 1/F=1/do+1/di. Our data is not exactly correct due to errors during the experiment.  For example, we determined when the image was in focus or out of focus using the human eye and judgement.  This was likely to give us slightly incorrect values for each trial.  We also had to measure a shaky image with a ruler.  The image was shaky because lab members had to hold the light in place while we measured the heights and distances.  Our values could have been slightly off due to the shaking of the lasers.