Planck’s Constant

Description

SP4-1986
Modern LEDs (light emitting diodes) cover the range from
deep blue (430nm) to infra-red (950nm). 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. The system is an excellent illustration of modern
electronics and gives a good investigation into a difficult
topic. The LEDs are mounted on a self-contained box
with voltage control and monitoring points for current and
voltage. A protection resistor is included to prevent damage
to the LEDs. Complete with viewing tube but without power
supply which should be approximately 5V d.c. from any
laboratory source.
SP4-1986