## Photoelectric Effect

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Color 1: Blue

 %Transmission Stopping Potential Approx. Charge Time 100 1.34 4 80 1.3 3.5 60 1.27 4.9 40 1.25 8.2 20 1.26 9.2

Color 2: Green

 %Transmission Stopping Potential Approx. Charge Time 100 .76 5.2 80 .76 7.2 60 .75 7.5 40 .75 8.8 20 .74 11.5

Experiment 1, Part B

 Light Color Stopping Potential Yellow .685 Green .795 Blue 1.378 Violet 1.89 Ultraviolet 1.91

Analysis:

1) Passing different amounts through did not have any major effect on the stopping potential and the same is true for its maximum energy. The charging time was increased with less light.

2) Different colors correlated to different stopping potentials with smaller wavelengths producing higher potentials and maximum energies.

3) A quantum theory because the charging time was increased with less light while the stopping potential remained the same.

The intensity of the light was smaller, meaning that less photons were able to flow through the filter and the stopping potential had to lower to compensate.

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 First Order  Color Wavelength (nm) Frequency ( Hz) Stopping Potential (volts) Yellow 576 5.2 .685 Green 545 5.5 .795 Blue 435 6.9 1.378 Violet 411 7.3 1.89 Ultraviolet 366 8.2 1.91

 Second Order  Color Wavelength (nm) Frequency ( Hz) Stopping Potential (volts) Yellow 576 5.2 .684 Green 545 5.5 .802 Blue 435 6.9 1.361 Violet 411 7.3 1.835 Ultraviolet 366 8.2 1.84
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Discussion Questions:

1) No, the stopping voltage does not depend on the light's frequency, only it's intensity.

2) Yes, the stopping voltage depends on the intensity of the light. A higher intensity begets a higher stopping voltage which begets a higher maximum energy.

3) Yes, before the photoelectrons are emitted they first need to absorb enough energy.

4) Yes, the frequency of light determines how many particles are hitting.

5) No, there is a minimum intensity that must first be met and outside of that the intensity does not matter.

6) No, the transfers of energy do not rely on each other; they are independent.

7) Both are supported.

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