Planck’s Constant

Modern LEDs (light emitting diodes) cover the range from deep blue (440nm) to infrared (940nm). 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 deduced. Complete with viewing tube but without power supply with stackable lead red 2pcs. & black 3pcs.