Tagged Questions

0
votes
2answers
39 views

Paraxial rays and marginal rays question

Paraxial rays are found to focus far away the lens whereas marginal rays focus near to the lens, why? I didn't find satisfactory answer in my academic book..
0
votes
1answer
65 views

How to calculate beam spread of a non-point light source via an aspheric lens

I need to determine the angle, or rate of divergence of light from a single aspheric lens when I place a non-point light source (e.g. LED array) at a given distance from the lens which is less than ...
0
votes
2answers
312 views

Magnifying Glass-How does it work? [duplicate]

How does a magnifying glass work? I know it creates a virtual image of the observed object but how is it possible that humans can see the virtual image?
0
votes
0answers
41 views

How does a lens affect the field of view in a mirror?

If one looks into a mirror, he can see a certain field of view. If he places a convex lens that magnifies (or a concave lens that does the opposite) in front of the mirror, but so that he can still ...
14
votes
3answers
387 views

What are these rays that appear in photograph of sun?

In many images of light emitting objects we see such rays. Why do they appear ? What is the math behind their number and direction?
-4
votes
1answer
70 views

Photonics: Slab As a Lens [closed]

The question can be found here: http://gyazo.com/fc4d26cd35e6ce368ad2a8ed504f1dcc The refractive index it references can be found here: http://gyazo.com/94fd2f3b5ea7da9226c3acd56b0024c1 I'm not ...