PURPOSE: To measure the speed of light.
DESCRIPTION: A pulsed laser diode is controlled by a function generator set at 1 MHz. The laser is aligned on an optical rail and aimed at a detector. The signals from the function generator and the detector are displayed on an oscilloscope.
The speed of light is observed by moving the detector along the optical rail. It is observed to be 13 centimeters per nanosecond (13 cm/ns), approximately 1 foot per nanosecond.
EQUIPMENT: Pulsed laser diode, function generator, oscilloscope, laser diode detector, optical rail, mirror.
SETUP TIME: The laser is auto collimated to be parallel with the optical rail. A mirror is aligned to reflect the beam.
