All Questions
282
questions
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votes
0
answers
35
views
Luneburg lens in a medium
A Luneburg lens is a spherical lens with a gradient refractive index. It has the interesting property that light coming from focal length of infinity will be focused on the surface of the lens.
The ...
- 284
0
votes
0
answers
34
views
How will Newton's rings look using a Concave-convex lens?
I want to examine lenses that are concave-convex (one for each side) using the Newton's rings method.
I'm trying to build the theoretical model for this, but I'm quite sure that the rays of light will ...
15
votes
2
answers
2k
views
Eye Floaters Optics
Eye floaters are these annoying objects floating in someones eye, usually seen by someone experiencing them as squiggly lines and dots buzzing around, either dark or partially transparent (I ...
- 153
0
votes
2
answers
33
views
Intuitively understanding virtual images in a multi-(thin)lens system
Let's say there is a multi-lens system of a converging lens (ex. a biconvex) and then a diverging lens with an object on the left of the system. And furthermore, let's say that due to the specific ...
0
votes
0
answers
25
views
How to Calculate Focal Length when in another medium?
How do you calculate the focal length of a lens when it is placed into another medium, if I only have the focal length of a lens in the air? I understand that the lensmaker's equation should be used, ...
- 187
2
votes
3
answers
224
views
What is the apparent location of a real image formed by a lens? [duplicate]
Let's say I place a tennis ball 1 m in front of a plane mirror. The mirror will form a virtual image of the tennis ball, and if I look in the mirror, it appears to me that there is a tennis ball ...
- 8,343
1
vote
0
answers
32
views
Best High Zoom Lens Configurations [closed]
Just wondering which lens configurations are usually best or most optimal for achieving high zoom in the smallest space or with fewest lenses.
E.g Let's say we want to achieve a 1000x magnification. ...
- 21
0
votes
1
answer
45
views
What is a convex-concave lens?
I came across this term while studying for optics, and I'm unsure as to what this means. My thinking is that it might be a meniscus lens, but the text separately give two different models for each ...
- 187
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votes
2
answers
56
views
Spherical aberration of lens
Why is spherical aberration absent in an image formed by a plano-convex lens on its principal axis? Will it be present in other types of lenses?
- 3
0
votes
1
answer
40
views
Formula for power of a lens submerged in a medium
I was always of the opinion that the power of a lens would invariably be the reciprocal of its focal length, irrespective of the medium surrounding it. However, I ran into a slightly different formula ...
- 47
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votes
0
answers
65
views
How do you derive the formula's for equivalent focal length and back principle plane for 2 thin lenses separated by a distance?
I've found online that the formula for the effective focal length of 2 lenses separated by a distance is:
$$
\frac 1f=\frac 1{f_1}+\frac 1{f_2}-\frac d{f_1f_2}.
$$
However, I'd like to know how this ...
- 101
0
votes
0
answers
23
views
Printing 2d fresnel zone plate
Recently my teacher asked me to create a Fresnel zone plate (Fresnel lens to be accurate).
I wanted to print it using a laser printer with a resolution of 1200*1200 dpi. I know that i should block ...
2
votes
1
answer
201
views
Lenses and missing reflection
I am wondering why reflected rays are not considered with lenses. If a ray strikes a surface, another is reflected off that striking point; however, this is not added when studying lenses, only ...
- 23
0
votes
0
answers
18
views
Final image formation in these 2 cases:
Can someone please explain simply how we determine how many times we have to consider reflection and refraction to obtain final image.
Example a:
Here they only considered refraction twice to obtain ...
3
votes
1
answer
75
views
Why is there no "parabolic abberation" in lenses?
I am trying to understand what an "ideal" lens would look like. Spherical surfaces are not correct, as these produce spherical aberration.
This article here, is really useful. It 'derives' ...
