Question

Collect the information about the lenses available in a optical shop find out how the focal length of a lens may be determined by the given power of the lens

Answer 1

power is a ability of a ray of light to converge or divergent in a given prism
p=1/f
p=power
f=focal length
as f is inversely proportional to n
then power become directly proportional to n
p1/p2 = n1/n2
as refractive index increase power of lens increase and focal length decrease

Answer 2

Answer:

   There are usually Biconcave and plano-concave lenses, Biconvex and Plano-convex lenses and cylindrical lenses available in the optical shops.  There are some other lenses too available.

   The convex lenses correct short sight.  The concave lenses correct long sight problem.  The cylindrical lenses correct distortion of objects due to astigmatism.   There are other types of spectacles which do correct color defects and others...

  Power of a lens P = 1/f     where f = focal length in meters.

 

  so f = 1/P     where P is expressed in Diopters.

Explanation: