The objective of this lab was to verify Planck's constant by essentially messing around with two LEDs.
Note: this lab was completed very quickly after class and the opportunity for photographs was very scarce. Only one unclear photograph was collected.
The wavelength that each LED projects was found. And the Voltage across each LED was also measured. Next the wavelength was graphed versus 1/E. Furthermore, the graph suggest that the slope is h*c , where c is the speed of light. Thus diving by c should yield Planck's constant. Note multiplying the voltage by charge gives one energy.
For the first LED, 1.95 volts and a wavelength of 590 nm (yellow) were measured.
For the second LED, 2.76 volts and a wavelength of 450 nm (blue) were measured.
Since the graph is not very clear, the slope will be calculated manually.
--> rise/run = h*c --> h = 3.1(10^-15) ev*s.
Multiplying by 1.6 (10^-19) J/1 ev yields --> 4.96 (10^-34) J*s.
This is not too far from the accepted value 6.63(10^-34) J*s. The percent error is very large at 25%. However the error stems from the equipment. If more time was given for completion of the lab, more LED lights would have been subject to test. Inevitably this would have produced a much better slope. Nonetheless all things considered, the degree of magnitude is the same.
