Light velocity measurement apparatus - employs balanced rotating mirror fitted with prism for deviating returned beam and uses laser as light source (SW210676)

摘要

The Foucault method for measuring speed of light uses a mirror rotating at high speed. A fixed prism or mirrors deviate the returned beam of light eliminating use of an unbalanced and therefore dangerous rotating mirror. Light (9) from a laser source (1) strikes a high speed rotating mirror (2) and is directed through a converging lens (5) and via a mirror (6) onto a second mirror (7) at the focus of the lens. Reflected light (10) returning towards the rotating mirror is deviated by a prism (8) which receives all light directed to the upper part of the mirror (2). Deviated light is directed onto a ground glass screen enabling observation of change in angle of light from the mirror rest position to the rotating position thus enabling measurement of speed of light.