how can i find Cylindrical and Spherical power of a spectacle
2007-01-23 19:21:25 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Engineering
The theory is simple. Find the focal length in metres and the inverse of the focal length in metres is the power expressed in dioptres. So, if a convex lens which has focal length of 0.5 m, its power is +2. For concave lenses, the power is expressed as - 1, - 2 etc.
In the case of convex lenses (with power +), it is possible to measure their focal length by moving a piece of paper and seeing where a far of object gets focussed.
2007-01-23 20:03:02 · answer #1 · answered by Swamy 7 · 0⤊ 0⤋
Its not easy to find it out at home. It needs lot of optical instruments and mathematics. I am not very sure about the process. To see one of that process visit -
http://www.everypatent.com/comp/pat5737059.html
To know the power of old spectacles I go to GKB Optics in my city. They have the equipment to check power.
2007-01-23 19:29:18 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Go to an optician
2007-01-23 19:24:18 · answer #3 · answered by Anonymous · 0⤊ 0⤋
I think you do light ray trace and find focal points.
2007-01-23 22:25:40 · answer #4 · answered by Anonymous · 0⤊ 0⤋
go to an optician
2007-01-23 19:23:19 · answer #5 · answered by Az 3 · 0⤊ 0⤋