Physics307L:People/Gibson/Notebook/070910

Setting Up

To begin this lab

Experiment 1 - The Photon Theory of Light

NOTE: DVM reads incorrectly for producing a 0 potential through the h/e apparatus. It reads at a (+) .04V

All measurements are using the first order spectral lines with the Variable transmission filter.

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Ultra-violet maxima stopping voltage readings - (NON TRANSMISSION LENS - 2.15)

2.09V in 3.06 seconds at 100%

2.09V in 4.89 seconds at 80%

2.09V in 5.49 seconds at 60%

2.09V in 6.99 seconds at 40%

2.09V in 9.69 seconds at 20%

Violet maxima stopping voltage readings - (NO TRANSMISSION LENS - 1.78)

Previously we calculated these values: 1.73V in 5.91 seconds at 100%

1.73V in 3.83 seconds at 80%

1.73V in 3.53 seconds at 60%

1.73V in 4.18 seconds at 40%

1.73V in 8.70 seconds at 20%

They turned out to be somewhat incorrect NEW VALUES:

1.74V in 3.63 seconds at 100%

1.74V in 5.37 seconds at 80%

1.74V in 5.58 seconds at 60%

1.74V in 7.71 seconds at 40%

1.74V in 14.90 seconds at 20%

Blue maxima readings - (NO TRANSMISSION LENS - 1.57V)

1.53V 4.71 seconds - new trial 1.97 100%

1.53V 3.70 seconds - new trial 3.13 80%

1.54V 2.70 seconds - new trial 4.03 60%

1.54V 3.50 seconds - new trial 5.76 40%

1.54V 6.69 seconds - new trial 6.60 20%

Green maxima stopping voltage readings - (NO TRANSMISSION LENS .91V W/O GREEN FILTER 1.05V)

.91V 6.91 seconds at 100%

.90V 8.15 seconds at 80%

.90V 10.90 seconds at 60%

.90V 16.99 seconds at 40%

.90V 26.77 seconds at 20%

Yellow maxima stopping voltage readings - (NO TRANSMISSION LENS .77V W/0 YELLOW FILTER 1.11V)

.76V 5.62 seconds at 100%

.76V 6.17 seconds at 80%

.76V 8.73 seconds at 60%

.76V 15.03 seconds at 40%

.76V 30.65 seconds at 20%

In our search for determining how to figure out the frequency order of the color spectrum we (Matt G and I) found a wiki website: Color spectrum and for EM spectrum where we obtained most of our formulas and the actual value of Planck's constant.

[math]\displaystyle{ \lambda = \frac{c}{f} \,\! }[/math]

and

[math]\displaystyle{ E=hf \,\! }[/math]

or

[math]\displaystyle{ E=\frac{hc}{\lambda} \,\! }[/math]