Light speed measurement

A desktop apparatus for the accurate determination  of the speed of light in free propagation (accuracy is 0.1% for a single measurement).

This apparatus is
– highly portable (fits into a small suitcase and in a tube of 130 cm length),
– pre aligned (no alignment necessary)
– quickly operative (setup in less than 1 minute)

It allows also measurements of:

– refraction index of solids and of small volume of liquids
– “velocity factor” of coaxial cables

No oscilloscope, no generator, no auxiliary equipment is required.

The apparatus’ sensitivity is so high that it detects the slowing of light
as it passes through the thickness of a microscope slide (about 1 mm )

See: G. Pegna G. Pegna , An extraordinary tabletop speed of light apparatus American Journal of Physics 85, 712 (2017)


Large version for museums and science centres on request.

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