# Questions tagged [reflection]

This tag is for questions relating to reflection, the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated. A familiar example of reflection comes from water waves; as the waves travel they reflect off objects that are floating in the water, and also reflect off the walls of the container holding the water.

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### What is the fundamental difference between Fresnel's reflectivity coeffecient and Bragg's scattering coefficient?

Context: In Chapter 3.1.2, Polarisation properties of surface backscatter, in the book "Polarisation: Applications in Remote Sensing", Dr Cloude explains scattering from a surface using ...
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### Is there a wavelength shift between sunlight observed from the ISS versus from Earth's surface?

As gasses are not ideal in transmitting sunlight. Are there differences between sunlight observed from beyond the Earth atmosphere and the one observed from the Earth surface? If so, what are they?
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### Relativity problem about light signals and rockets equipped with mirrors [closed]

I find in a relativity book a problem that states: "A rocket with its own length $L$ moves away from Earth at a constant velocity $v$. A radar signal emitted from a ground station is reflected ...
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### Convergence of rays at focal plane after reflection from concave mirror

My teacher taught us that rays parallel to each other(but not necessarily parallel to the principal axis), after reflection from a concave mirror,get converged at a sharp point somewhere on the focal ...
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### Huygens' principle and the laws of reflection/refraction

As I understand the Huygens principle, all points on the wavefront are sources of secondary spherical wavelets and the tangent to these wavelets will form new wavefront. This is used to prove the ...
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### My explanation of interference contradicts known result (standing waves) - did I add phase wrong?

This is based on question 5d from this A-Level Paper (OCR A 2023 Paper 3): Plane-polarised microwaves are sent out from a transmitter aerial to a parallel receiver aerial. Behind the receiver, along ...
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### What percentage of light gets scattered by a mirror?

Sunlight strikes a mirror at a 45 degree angle. The vast majority of light will be reflected about the normal. Some light will be absorbed by the mirror. Some light will be transmitted through the ...
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### Is there a name for the number of '9's in numbers such as 0.999 (where it would be 3)?

I am doing an optics simulation involving transmission and reflection coefficients very close to 1, such as 0.999. While I was an undergraduate student, a professor mentioned that, in certain fields, ...
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### $\pi$ phase shift upon reflection in quantum wells

Is there a similar phenomenon to the $\pi$ phase shift experienced by light upon reflection from a medium of lower to higher refracted index for particles in different potentials? For instance, does a ...
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### How is partial reflection of light by two surfaces explained?

I am reading QED by Richard Feynman and he explains how changing the thickness of glass results in a change in the probability of photons reflecting off the glass back to the photomultiplier. However, ...
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### Beam displacement at focal point

I'm working on a project that uses galvanometers with mirrors. They're configured to have a focal point of 175mm. The motors rotate at 1 mechanical degree per 500mV, that will be 2 degrees optical per ...
1 vote
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### What happens when a linear polarized EM wave encounters a perpendicular mesh of wires (which are electrically connected)?

Assume a radio wave with wavelength 1 m is traveling in the negative z direction when it encounters a grid of closely spaced wires (say, 10 cm separation) laying in the xy plane, with each wire ...
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### Does a mirror have an albedo of 0?

According to the Wikipedia definition of albedo, it measures the fraction of light that is diffusely reflected by a body. Let's consider the visible light wavelenghts; is a mirror an object with an ...
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1 vote
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### How to determine if an observer can see an object with multiple mirrors?

How do I determine if an observer can see an object with multiple mirrors? I came across this image online and I am wondering if the observer (point O) see the object (point A) My attempt: I tried ...
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### How does the mirror know what’s behind the paper?

I found this on social media. Although it was posted for fun, this is a valid question: How does the mirror know what’s behind the paper? Show me how light reflected from the egg reaches the mirror.
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### Pointing flash at LCD television creates a weird diffraction effect

I was looking around my room for something with my phone’s flash on, and noticed a very unique pattern reflecting off of the television. FYI. The flash is white. Any idea why it diffracts like that? ...
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### Reflection due to wave nature of light

In my high school, I am studying geometrical optics. I studied why smooth surfaces like mirrors form an image of an object but rough surfaces like a wall don't (due to regular reflection and irregular ...
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### Electromagnetic reflection without velocity change

The Fresnel equations describe the reflection and transmission of electromagnetic waves between two media. The parameter in the equations is the impedance ratio, where the impedance is $Z=\mu/\epsilon$...
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