Encyclopedia > Diopter

  Article Content

Dioptre

Redirected from Diopter

A dioptre (also diopter) is a unit of curvature equal to one per metre. A circle with radius 1/2 metre has a curvature of 2 dioptres. It is also used to measure focusing power of lenses and (curved) mirrors; the power is the inverse of the focal length. Diverging lenses have negative power.

If the curvature of a lens is C and the index of refraction is n, the focusing power is F=(n-1)C. If both surfaces of the lens are curved, consider their curvatures as positive toward the lens and add them. For a mirror the focusing power is F=2C.



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
Holtsville, New York

... versus $31,709 for females. The per capita income for the town is $24,031. 3.6% of the population and 2.4% of families are below the poverty line. Out of the total people ...

 
 
 
This page was created in 35.1 ms