Photoelectric Effect Apparatus
Photoelectric Effect Apparatus
TEL-310
The Photoelectric Effect demonstrates that the energy of a photoelectron depends on the wavelength of the incoming radiation and not on its intensity. While monochromatic radiation irradiates the photocathode, a potential is applied opposing the energy of the emitted electrons. The voltage required to just stop the current flow is proportional to the energy of the photoelectrons. Plotting this voltage as a function of the reciprocal of the wavelength gives a straight line plot. Students can use the graph's slope to calculate Planck's constant.
The apparatus includes three color filters to provide spectral separation. A small mercury arc monochromatic light source is available (TEL-ES1819). Results can be achieved with multiple laser wavelengths (pointers work well). Students can use a high power tungsten lamp with less precision. A digital voltmeter or datalogging equipment to measure the stopping potential is required.
TEL-310
The Photoelectric Effect demonstrates that the energy of a photoelectron depends on the wavelength of the incoming radiation and not on its intensity. While monochromatic radiation irradiates the photocathode, a potential is applied opposing the energy of the emitted electrons. The voltage required to just stop the current flow is proportional to the energy of the photoelectrons. Plotting this voltage as a function of the reciprocal of the wavelength gives a straight line plot. Students can use the graph's slope to calculate Planck's constant.
The apparatus includes three color filters to provide spectral separation. A small mercury arc light source is available (TEL-ES1819-2). Results can be achieved with multiple laser wavelengths (pointers work well). Students can use a high power tungsten lamp with less precision. A digital voltmeter or datalogging equipment to measure the stopping potential is required, but not included.