# Proposition: Construction of a Light Clock

In any inertial reference frame $$\mathcal I$$, it is (theoretically) possible to construct a light clock by placing two mirrors in a vacuum at a fixed distance $$d$$ and letting a light particle "bounce" between them. The "tick duration" of such a light clock is then given by the formula

$\operatorname{tick duration}:=\frac dc$

where $$s$$ denotes the time unit of one second, and where $$c$$ denotes the (constant) speed of light in a vacuum:

$c=299.792.458 \frac{\operatorname{m}}{\operatorname{s}}$

The following figure demonstrates a model of a light clock:

### Examples

In particular, if $$d=1m$$, the tick duration of this clock in $$\mathcal I$$ is

$\frac dc=\frac {1m}c=\frac {1m}{299\,792\,458\frac ms}=\frac {1}{299\,792\,458}s.$

For $$d=299\,792.458\,m$$ the tick duration would be

$\frac dc\approx\frac {299.8\,km}c=\frac {1}{1000}s=1\,ns.$

Proofs: 1

Definitions: 1
Proofs: 2

Thank you to the contributors under CC BY-SA 4.0!

Github:

### References

#### Bibliography

1. WeingĂ¤rtner, Andreas: "Spezielle RelativitĂ¤tstheorie - ganz einfach", Books On Demand, 2016