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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1answer
14 views

Lens and plane mirror: inverted or not?

In a situation like this, I understood that the focal length is half of that of the original lens. However, I don't know whether its image is inverted or not. In this situation, will the image be ...
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5answers
2k views

Physical difference between moonlight and sunlight

Night-blooming cereus are plants that only bloom at night. Their light-sensitive cells must be able to tell the difference between sunlight, and sunlight reflected off the moon. What is the physical ...
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0answers
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Focal length of concave mirror with water

I want to find the focal length of mirror in the picture below. I know that beetween air and water the refraction happens, then light passes throuh water with thickness $d$, then it bounces on the ...
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1answer
25 views

Changes in imaginary dielectric function to changes in Absorptivity of material

I have a quick question that I am trying to get my head around. I am the looking at the increased absorption of light in some metal as temperature is increased. Lets say that the imaginary dielectric ...
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1answer
32 views

In a rainbow, why is the top colour red and violet on bottom even though red emerges farther (42 degrees) than violet (40) when seen in a single drop?

I don't understand this image or why primary rainbow has red at the top even though in a single drop red is deviated most.
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1answer
186 views

How thin can the wires of a sub-wavelength gold mesh be and still be half as reflective as a solid sheet? What physics dictates this?

A metal wire mesh can be nearly as reflective to an incident EM wave as a solid sheet of metal provided the wires are sufficiently conductive and the size of the mesh is much smaller than the incident ...
3
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1answer
191 views

If a photon strikes a perfectly reflecting mirror, it is essentially at rest at the instant of collision. So why does the photon exist?

Photons can only move at the speed of light.how do we define its existence at the instant when it collides with a perfect mirror?
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0answers
10 views

What is Transverse linear increase?

I saw this term in a Optics Book inside the chapter of spherical mirrors(but also might be related to gaussian mirrors), and I was wondering, what it this Linear increase, if spherical mirrors don't ...
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0answers
16 views

Cause of 180 degree phase shift of reflected light [duplicate]

When light originating from a medium of lower refractive index reflects off a surface of higher refractive index, why does the phase shift by 180 degrees? Stokes relations show that the reflection ...
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0answers
13 views

Cross-polarization viewing from different angles are not consistent?

I'm trying to utilize cross-polarization to eliminate reflections on objects in photography. I use linear polarizing filters on multiple light sources (polarized lights are my only light sources, no ...
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0answers
15 views

How to eliminate light in Fresnel reflection to human eyes?

Dose light lose its polarization when in Fresnel reflection? If so, how to eliminate if through polarizing filters or other setup, in terms of viewing by human eyes or cameras?
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0answers
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How full img formed even we cover half of plain mirror?

When we cover half plain mirror does we get full image of object? Or only that part ie above that cover? (Virtual image not real) Many ppl say full image will form even in plain mirror but if i cover ...
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0answers
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How full img is visible after covering half plain mirror? [closed]

What happen to my img if u cover plain mirror with black sheet halfly? Many say i will saw complete image but hiw i tried and find only portion above that black paper is visible if mine? Than how ...
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1answer
35 views

Qualitatively Brewster angle explanation with dipoles

The qualitatively explanation of the Brewster angle (e.g., see https://en.wikipedia.org/wiki/Brewster%27s_angle) is that incident light produces small electric dipoles on the surface of the dieletric ...
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0answers
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Can someone explain to me why the fringes would move apart in this air wedge?

Consider two identical microscope slides in air illuminate by monochromatic light as shown below. A pattern of interference fringes is formed. If the wedge angle gets smaller, the fringes move further ...
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1answer
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Feynman Vol-I 33-6 The intensity of reflected light. Are the given reflection coefficients the squares of what are typically used?

From https://www.feynmanlectures.caltech.edu/I_33.html#Ch33-S6 We have assumed unit amplitudes for the incident waves, so that $\left|B\right|^2/1^2$ is the reflection coefficient for waves polarized ...
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4answers
2k views

Why does the light of this infrared laser become visible after reflection?

We use a 780 nm laser in our lab, and that makes it in the near infrared (IR) range. The majority of people can not see this wavelength of light. However, when the beam reflects off of an object (see ...
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0answers
28 views

Is there an approach to explain miror reflection different than Feynman's?

In "The Strange Theory of Light and Matter" Richard Feynman uses a "stop-watch" to time the photon as it moves. For each photon path, the final direction of the hand is considered ...
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0answers
60 views

Time generalized Biot-Savart and Coulomb laws: Jefimenko's Equations, boundary-conditions, reflection, transmission

I am attempting to use the time generalised Biot-Savart and Coulomb laws (sometimes called the Jefimenko's equatios) to calculate the electric and magnetic field of a wire loop in a homogeneous sphere ...
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2answers
48 views

Why is the graph of a linear relationship curved?

In light phenomena (lenses and mirrors), we know the formula $\frac{1}{v} + \frac{1}{u} = \frac{1}{f}$ which describes the relation where, $v$ = the distance of the image from the mirror $u$ = the ...
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1answer
52 views

Could I see the corner of the room?

Could I see the corner of the room I'm in, if all walls had the same color and were perfect Lambertian reflectors?
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0answers
21 views

Reflection of EM waves on furniture

I just put my phone next to a piece of furniture with wood finish on it. The reflection of the wood on the wood was purple-ish in appearance. What is the Physics behind this?
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28 views

Does reflection depend on wavelength?

I'm aware of processes like Rayleigh scattering, Compton scattering and pair production. But as these processes treat light as being particles(?) I'm not sure whether they are helpful to understand ...
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2answers
73 views

Mirror moving near the speed of light

Suppose I am looking at a moving mirror, the image will move at twice the speed of the mirror but what if the mirror was to move with half the speed of light? How will my image look and what if the ...
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0answers
28 views

Why we can see images behind a concave mirror despite it forming real images in front of it?

Why we can see images behind a concave mirror despite it forming real images in front of it? Many say it is illusion of the eye but if so, how can I even see it in mobile pictures? And all rays from ...
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0answers
14 views

Multiple beam reflection and sharp fringes

Why multiple beam reflection method interferometry produces sharp fringes? I came across this assertion while reading Fabry Perot interferometry. But i can't find the justification of it. Can anyone ...
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1answer
26 views

Image in concave mirror even from side? [duplicate]

After reading my ray optics chap, I am frustrated and cannot get an answer. As a concave mirror create real images, how can we see them on mirror? Now I know you will say it is an illusion, the image ...
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1answer
37 views

If a real image is formed at some distance from a concave mirror, how can we always see it, no matter where we are standing?

In a typical concave mirror experiment, the “real” image can only be focused at a specific position, where the light rays meet. Yet, if I look at some stationary object behind me in a stationary ...
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1answer
45 views

Does a retroreflector depolarize light or preserve polarisation?

In case the retroreflector is just a glas window, the Fresnel equations apply and for an incidence angle of $\theta = 0^\circ$ the reflectivities $R_p$ and $R_s$ for parallel and perpendicular ...
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1answer
29 views

Image of concave mirror when object is farther than the focal point

I have a set of concave/convex mirrors/lenses, and I have drawn out all of the ray tracing diagrams for each possible combination and type of image each optical element can produce. When I look at the ...
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1answer
20 views

What is the microscopic mechanism for the reflection of sound waves?

There are a couple questions similar to this but the answers don't quite answer what I want. In EM, the reflection of light is microscopically described an EM wave accelerating electrons that ...
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0answers
17 views

Newton's rings due to two equiconvex lens

An equiconvex lens is placed on another equiconvex lens. The radii of curvatures of the two surfaces of the upper lens are $R_1$ and those of the lower lens are $R_2$. The waves reflected from the ...
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3answers
106 views

Why does EM destructive interference reflect on an resonnant cavity chamber but not on a piece of paper?

Case 1) Light passing through a single or double slit with show an interference pattern on a screen with dark fringes. The observer eye wont receive light comming from the dark fringes (and therefore ...
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1answer
79 views

Why I see everything which is red in 3D with my prescription eyeglasses?

I have prescription eyeglasses with -1.5D power (Myopia). I have been wearing eyeglasses for past 5 years and recently changed to blue light filter ones. Now I recognise everything red in colour as a ...
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1answer
32 views

Would a non-dimensionless reflection coefficient make sense?

I am working with a numerical modelling program allowing to simulate wave propagation in a drill string. The reflected waves are modelled using the reflection coefficient between the drill bit and the ...
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2answers
44 views

Phase Shift of Light upon Reflection

In waves other than electromagnetic waves (e.g. waves on a string assuming small transverse displacement), when propagating across the boundary between two media, a fraction of a wave will be ...
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11answers
5k views

How can parallel rays meet at infinity?

I found that in every book (till my 12th) it is written that, in concave mirror, when object is at focus, then reflected rays will be parallel and they meet at infinity to form a real image. But, as ...
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2answers
210 views

How does a photon know what to do when It interacts with the first surface of a LIGO mirror?

There are 72 alternating boundaries (optical coatings) to traverse before it can decide whether to reflect or pass through the mirror. The boundary properties are such that the the first boundary by ...
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1answer
63 views

Does a white surface reflect more light than a mirror?

I read that a (sufficiently) white surface reflects more (visible) light than a mirror. Is that true? And if yes, why?
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2answers
39 views

How mirror can be used to explain the appearance of mirages?

Since mirage, in optics, the deceptive appearance of a distant object or objects caused by the bending of light rays (refraction) in layers of air of varying density. The normal path of light rays ...
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4answers
66 views

Source of light [closed]

Is this statement true" Chair is a source of light". We know that there are two types of source of light(1) Primary source of light ( like bulb, candle) (2) secondary source of light ( like ...
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1answer
71 views

Why don't we see rainbows from mirrors?

Should this not be the case whenever light strikes a thick mirror on the whole (obliquely)?? Someone please clarify.
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1answer
27 views

How to understand the Fresnel relation $1+R=T$? [closed]

From the perspective of energy conservation, we are familiar with the relation $T+R=1$ (Set the incident wave amplitude as 1, $T$ and $R$ are Fresnel transmission and reflection coefficient, supposing ...
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1answer
27 views

Massless particles and time synchrony

Someone once tried to explain to me why neutrino oscillation implies that neutrinos have mass, and I understood it as follows: Change requires time. Massless particles travel at the speed of light. ...
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2answers
81 views

Can speed of image in mirror exceed the speed of light?

Suppose I'm moving toward the mirror at the speed of v, then relative speed btw me and mirror would be v. And I thought that we can think like there exist world that is the same as our world inside ...
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8answers
3k views

Is it possible to create a mirror that redshifts light?

Mirrors are able to reflect light but are not perfect and after a number of reflections, light loses intensity. However I wonder, during the reflection by a different type of mirror, could the light ...
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2answers
64 views

If we can see the light reflected off objects, why can't we “see” light? [duplicate]

It's said that light is invisible because photons don't strike each other, then why we do see the reflected light from other objects?
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0answers
17 views

Answer different using effective focal length of combination of lens

Q)The figure shows a silvered lens. $\mu_A = 1.6$ and $\mu_B = 1.2$, $R_1 = 80$cm, $R_2 = 40$cm and $R_3 = 20$cm. An object is placed at a distance of 12 cm from this lens. Find the image position. I ...
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0answers
31 views

Double image forming in rear view mirror of car

I was just sitting on back seat of car when I noticed that the rear view mirror was making 2 images of my dad's face I tried to think of some reason but couldn't so I took some photos but only a shiny ...

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