Use the Coulomb's Law simulation by PHET.

Use the Coulomb's Law simulation by PHET

https://phet.colorado.edu/sims/cheerpj/photoelectric/latest/photoelectric.html?simulation=photoelectric

Here is a video example of collecting data for the Photoelectric effect lab from the April 22, 2021 online session:

https://youtu.be/3hhoCGtXt1Y

Observations:

1.Under the target menu, select the unknown cathode type (?????)

2.Turn the light intensity up to 100% and slide the wavelength to 150 nm (if you are having difficulty getting the slider to the right position, you can type the wavelength into the box instead).

3. Move the voltage slider until the current is stopped. You are looking for the first voltage value that stops the current. The electrons should make it all of the way across the tube and only turn around at the anode. If you are having trouble finding the exact stopping voltage value, you can type numbers into the battery voltage box to get the amount more exact.

4. make a data table for wavelength and stopping voltage. Record the first wavelength (150 nm) and the stopping voltage that you found in your data table.

Wavelength (nm)	Stopping Voltage (V)
150
160
170
180
190
200
210
220

4. Increase the wavelength in 10 nm increments and measure the new stopping voltage for each case. Record your values on your data table.

Analysis:

1. make a new data table for frequency (f= c / )in Hz , and kinetic energy in electron volts

(E_k = q V_stop). Include sample calculations for one data point to show how you calculated frequency and kinetic energy.

2. Plot a graph of electron kinetic energy as a function of frequency. Make sure that the y-intercept is visible (in google sheets you do this by modifying the minimum value under the horizontal and vertical axis tab).

3. Use the photoelectric effect equation (Ek=hfW) and the slope intercept equation to determine the physical meaning of the slope of your graph AND the physical meaning of the y-intercept.

4. Calculate the percent difference between your experimental value of your slope and the expected value.