A modern version of the “Photo-Electric Effect” by IEC for teaching this very important phenomenon and for the determination of “Planck’s Constant” to a reasonable accuracy. A choice of 5 different LEDs of known wavelength provide photons to a cell that generates electrons to create a very small current. A ‘backing voltage’ is applied to the cell to stop the current flow and this becomes the measurement of the energy level of the photon. These energy levels are plotted against the frequencies of the LEDs.
Major improvements of this model include: The backing voltage and the photo-cell current can be viewed together without switching from one to the other. LEDs are used as the specific wavelength light sources instead of an incandescent lamp and colour filters.
DETAILS:
Requires 12V AC or DC from either a mains PlugPak or from a classroom power supply. Provides 2x digital meters to read Backing Volts and Cell Current at the same time. 4x controls for: selection of LED colour, adjustment of brightness or intensity, the option of coarse and fine adjustment of Backing Volts.
• Includes set of 5 x LEDs of specific wavelength mounted on a small panel with cable & plug. Mounts on the rear of the instrument. The LED wavelengths are indicated on a label on the rear face of the instrument.
• Includes instructions (click here) and experiment sheets (click here).