Image 1 of 1
This apparatus is designed to determine the approximate value of Planck’s constant using the elbow voltage in the characteristic curves of a number of LEDs.
There are 7 LEDs covering from deep blue at 470 nm to near IR 940 nm mounted on the box with sockets for voltage and current measurements. By monitoring the voltage at which each LED just begins to emit light a graph of energy input as a function of light emitted frequency can be plotted and an approximate value of Planck's constant can be deduced.
Wavelengths: 470 nm, 505 nm, 570 nm, 605 nm, 655 nm, 880 nm, 940nm.
External power supply for 9 volts is required or a 9 Volts battery with suitable connecting cords can also be used.