## Experiment 1

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PART A:

% Transmission   Stopping Potential (V)      Approx. Charge Time (s)

100                      .812                               4s

80                        .812                               7s

60                        .811                               5.72s

40                        .811                               8.69s

20                        .811                               18.45s

Red Light (good timing results)-

% Transmission   Stopping Potential (V)      Approx. Charge Time (s)

100                      .67                                 1.26

80                        .67                                 1.49

60                        .66                                 1.71

40                        .67                                 2.16

20                        .67                                 2.66

PART B:

Light Color          Stopping Potential (V)        Frequency (Hz)

Yellow                .67                                    5.2*10^14

Green                 .79                                    5.5*10^14

Blue                   1.35                                  6.9*10^14

Violet                 1.55                                  7.3*10^14

Ultraviolet           1.84                                  8.2*10^14

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ANALYSIS QUESTIONS:

1) The intensity of the light seemed to have little to no effect on the stopping potential. This indicates that no matter how much light is getting through, the maximum energy of the light doesn't change which supports the quantum model of light meaning that the has its own quantity of energy and isn't defined by a wave whose energy would be diminished by a filter bringing down it's amplitude. However, the larger effect was had in the charging time. This makes sense because if less light is getting to the photo diode, regardless of which model being used, then it will charge slower (either due to a wave of less amplitude or due to smaller amounts of light of the same quantum energy reaching the photo diode).

2) The higher the frequency, the higher the stopping voltage. The energy being dependent on the frequency is one of the main ideas of the quantum model. Frequency is important, not amplitude.

3) The evidence and data behind question 1 is strong enough for me to say the energy not being equal steps cannot disprove the quantum theory. So in my opinion, based mainly on the explanation in question 1, that this experiment is in support of the quantum theory.

The apparatus isn't a perfect charge holder so as the energy from the light is filling the circuit, some of it is leaking out. Less light means it will take more time for the same energy to get into the circuit. When the intensity is high, the ratio of the fill rate to the leak rate is very large, but when the intensity is low, the fill rate to the leak rate is smaller. This means at lower intensities the light has a harder time charging the circuit and overcoming the leaking current.

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