The photoelectric effect was discovered in 1887 by the German physicist Heinrich Rudolf Hertz. In connection with work on radio waves, Hertz observed that, when ultraviolet light shines on two metal electrodes with a voltage applied across them, the light changes the voltage at which sparking takes place.
In the first procedure Ibegun with the relationship between frequency and KE. I collected all the data at the 8mm aperture which resulted in constant intensity.in the third column I recorded the stopping potential for each wavelength.
In the second procedure, I collected data on the 436nm filter keeping frequency constant and varying the intensity for each of the aperture sizes.
In the third procedure, I took all the data using 436nm filter with constant frequency
For a given frequency of light, if the voltage between the cathode and anode is equal to the stopping potential, the photocurrent is zero.
When the voltage between the cathode and anode is greater than the stopping voltage, the photocurrent will increase quickly and eventually reach sarturation.the saturated current is proportional to the intensity of the incident light.
Light of different frequencies have different stopping potentials
The slope of a plot of stopping potential versus frequency is the value of the ratio, h/e
The photoelectric effect is almost instantaneous. Once the light shines on the cathode, photoelectrons will be emitted in less than a nanosecond.
Example, conversion of wavelength to frequency with reference to procedure 1
Maximum kinetic energy;
The energy in light comes in small packets is called a quantum of energy or photon.
From this experiment it becomes clear that the low wavelength photons have high energy while the high wavelength photons have relatively low energy
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