# Tag Info

### How does the combination of lens create a sharper image?

It's hard to answer without knowing the context of the statement. But generally, multiple lenses can reduce aberrations. Real lenses aren't perfect, and images suffer because of that. Rays ...
• 21.3k
Accepted

### Rainbow reflections from salt crystals

I suspect the rainbow is from retroreflector glass beads rather than salt. Tiny glass beads are placed on the surface of road markings, halfway embedded, making them reflect light from vehicles back ...
• 26.7k

### Fourier Transform of a Wave Packet

Mathematicians usually put $1/\sqrt{2\pi}$ before each integral. Physicists usually leave it out of the integral like your first equation, but then divide the inverse integral by $2\pi$
• 1,104
Accepted

### Using a transparent cup of water as a magnifier

The cup (rather the water in it) simply acts like a thick cylindrical lens. When looking through it at an object close to the cup, it acts much like a magnifying glass, but one that magnifies only in ...
• 7,257

### Beam splitters- Direction of use

there is actually a difference between the two cases other than the diection of the reflected beam. Cube beamslpitters are constructed using two parts glued together using a special cement. The mirror ...
• 21
Accepted

### Geometric optics explanation of lateral (transverse) chromatic aberration

You are correct that the first picture is wrong. For a single refractive lens, the lens power will be greater for blue light, compared to red. Hence the focal length will be shorter. You are on the ...
• 601
1 vote
Accepted

### How does a rainbow show all of its colours?

The diagram produced in the question has a couple of errors and almost answers the question. To a very good approximation the rays coming from the Sun are approximately parallel and the reflection ...
• 76.9k
1 vote

### Can we tell on which side of a lens an image appears?

Yes, as shown below. Assuming the object is on the other side of the lens compared with the eye a virtual image is formed on the same side as the object whereas a real image is formed on the the ...
• 76.9k
1 vote

### Can we tell on which side of a lens an image appears?

The image is like a copy of the object (with appropriate scaling) at the location of the image. In particular, it produces the same depth cues as a real object would. If you can see both it and the ...
• 2,307
1 vote

### How does the combination of lens create a sharper image?

The distance between nerve endings in the retina of the eye places a limit on the sharpness of an image that you can observe. A good lens system can bring the image closer and larger. This can cause ...
• 11.4k
1 vote

### Why image of vertical object is always a straight line and perpendicular to principal axis?

The answer is that all points with the same distance $u$ image onto different points but with the same distance $v$. You can ask, "ok, but why", and the proof to that is actually not shown ...
• 3,724
1 vote
Accepted

### What happens when light gets reflected and refracted at the same point?

A perfectly narrow ray perfectly intersecting a point such as the one you’ve drawn is unphysical. Reflection and refraction are reliant on phase matching at a boundary, in which is implicit a length ...
• 10.5k
1 vote

### What happens when light gets reflected and refracted at the same point?

Your assumption is perfectly right here. When light falls on any surface a part of it is reflected, a part of it is refracted and the rest gets absorbed. If you try to visualize the picture in your ...
1 vote

### Rainbow reflections from salt crystals

Looks like, e.g., ice crystals can cause some rainbow-like effects. So maybe salt crystals or some other crystals can cause the effect in your video. It seems that in your video the rainbow is present ...
• 23.6k

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