What is Reflection: Definition and 953 Discussions

Reflection is 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. Common examples include the reflection of light, sound and water waves. The law of reflection says that for specular reflection the angle at which the wave is incident on the surface equals the angle at which it is reflected. Mirrors exhibit specular reflection.
In acoustics, reflection causes echoes and is used in sonar. In geology, it is important in the study of seismic waves. Reflection is observed with surface waves in bodies of water. Reflection is observed with many types of electromagnetic wave, besides visible light. Reflection of VHF and higher frequencies is important for radio transmission and for radar. Even hard X-rays and gamma rays can be reflected at shallow angles with special "grazing" mirrors.

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  1. Monoxdifly

    MHB [ASK] Reflection of a Line by Another Line

    The reflection of the line 5x - 7y - 13 = 0 by the line y = -x is ... A. 7x + 5y - 13 = 0 B. 7x + 5y + 13 = 0 C. 7x - 5y - 13 = 0 D. 7x - 5y + 13 = 0 E. 7y + 5x + 13 = 0 This one I totally have no idea. Like, at all.
  2. DaTario

    Reflection of light in metallic surface and glass

    Hi All, Due to the differences in their conductivities, but considering that both the metallic and the glass plane surfaces produce mirror images of objects, is there any difference in the explanation of the mechanism of reflection of light in these materials?
  3. Sheldon11

    Reflection Grating: How Does it Diffract?

    How a reflection grating works as diffraction source?
  4. Dimani4

    Definition of transmission & reflection in TE/TM

    Hi, I have a question in definition of reflection/transmission coefficients in TE/TM modes. Let's see TE polarization case. The reflection coefficient for the magnetic field is defined as: However the transmission coefficient for the magnetic field is defined as: Now, let's see the TM mode...
  5. P

    B Understanding Reflection in Light: Electromagnetic Interactions with Matter

    If light encounters -normal- matter, the electromagnetic aspects of the influence of the electrons will be interacted with (I'm ignoring any stress contributuins to gravity) which is (scattering matrix?) either nothing at all (translucency) due to quantisation, or absorbtion. Is this correct...
  6. P

    A Reflection or emission of a photon

    Hi, if I read the article (see link) I get confused: Is it emission or reflection? If it is emission, how is it possible that the photons are emitted to one side? (Unfortenately I do not have access to the original article.)...
  7. D

    Meaning of the FFT of a Poynting Vector integral, reflection coefficient

    Hello, For calculating the mean power at a specific cross section of a waveguide, one can calculate the mean value of the temporal function of Poynting Vector, P(t), where P(t) is the ExHy-EyHx. Note that I am not talking about phasors or a sinusoidal state. If I integrate over the waveguide...
  8. C

    Does a Single Metal Stripe Reflect Polarized Light at the Angle of Incidence?

    I know that only light with polarization in the plane of the "stripe" gets reflected. What i need to know is if a single metal stripe could reflect such polarised light at ONLY the angle equal to the angle of incidence or do only a whole array of stripes produce specular reflections? Sources...
  9. C

    Will a subwavelength conductor patch reflect specularly?

    If I had metal stripe significantly longer than the wavelength but less wide than one wavelength and it would be at an angle in the plane perpendicular the length of the stripe to to the incoming wave, would itireflect specurarly or diffusely?
  10. Richie Smash

    Determine matrix for reflection followed by rotation

    Homework Statement Hi good morning to all. The problem at hand states, that the points A (3,0) and B (5,0) are reflected in the mirror line y=x. Determine the images A' and B' of these points. I've done that using the reflection in the line y=x which i know to be \begin{bmatrix} 0 &1 \\ 1 & 0...
  11. GAURAV DADWAL

    B Michelson-Morley Exp: Laws of Reflection Explained

    Hello there, I have a problem with this image from the Michelson Morley experiment in which one tries to calculate the time taken by the light beam to traverse the arm of interferometer perpendicular to the velocity of the frame in 'ether'. So the problem is, Are laws of reflection being...
  12. S

    I Total reflection in Feynman picture

    In his popularized version of QED (Strange Theory...) Feynman explains reflection from an air-water boundary (including total internal reflection) by summing up the amplitudes of various paths that bend at the boundary but are straight everywhere else. As we add more contributions, we see a...
  13. J

    Phase Change and Reflection of Electromagnetic Waves

    Homework Statement Note : There are no minus signs in first two options . Homework EquationsThe Attempt at a Solution The wave is propagating in +z direction whereas the electric field is varying in x direction . On reflection , there is a phase change of π . Also wave starts traveling in...
  14. C

    Phase/group refractive index and reflection

    Let's consider a simlified ionosphere. It is a cold plasma without magnetic field and without electron-neutral collisions. The refractive index for radio waves is nf=sqrt(1-(w/wp)^2) (w is the frequency of the radiwave, wp the plasma frequency). It easy to demonstrate that the group refraction...
  15. I

    Maximum/minimum reflection | Thin-film interference

    Homework Statement A transparent film( n = 1.45) is placed on a glass surface( n = 1.14) and is illuminated by light ( incidence angle α = 60°. What is the minimum thickness d1 of film such that reflection of light with λ is minimized, while if the thickness is d2 then with the same λ the...
  16. Wrichik Basu

    How can this interesting set of mirrors be constructed?

    The mirror that I'm talking of, is situated in Hazarduari Palace in Murshidabad, West Bengal, India. This place was once the capital of Bengal under the Nawab before the British defeated the Nawab in the historic battle of Plassey, 1757. The history is not that important here, but the mirror...
  17. V

    B Reflection of light from the mirror

    What is exactly happening when the light hit a surface of a mirror? I know it is not same as a bounce of ball from the wall, because of constant speed of light for example. So I suppose the light is absorbed by electron of reflecting material. This probably define the materials who are...
  18. I

    The Contrary Laws of Reflection

    So, I was just working out on color and reflection but then turned a little bit confused. The main phenomenon we study everywhere is that a colored object absorbs light of all wavelengths excepting the light of its own color. Then comes the problem. As per that, if I beam a GREEN LASER on a RED...
  19. Rodrigo Schmidt

    Why does the pulse related to the inverted phase travel to the right?

    So I'm having a introductory study on waves and there's something that i can't understand when dealing with reflections on a fixed end. We have the general solution for the wave equation: ## y(x,t)=f(x-vt)+g(x+vt)## Supposing that the fixed point is in the origin we have the boundary condition...
  20. Cocoleia

    How does reflection affect the intensity of the microwave?

    Homework Statement I am working on a lab report, and I am a bit stumped at these questions: How does reflection affect the intensity of the microwave? Is all the energy of the wave striking the Reflector reflected? Does the intensity of the reflected signal vary with the angle of incidence...
  21. B

    Gaussian beam spherical mirror reflection question

    Homework Statement Gaussian beam of radius R_i and beam width w_i, The beam is reflected off a mirror with a radius of curvature R = R_i and the reflectivity of this mirror is given as rho(r) = rho_0*exp(-r^2/a^2), where r is the radial distance from the center of the mirror and a is a...
  22. G

    What happens to the electric field's phase upon reflection?

    I have a problem with the phase of an electric field as it is reflected by and transmitted through a dielectric interface. At the boundary between the two media, all waves must exist simultaneously and the tangential component must be equal on both sides of the interface, right? Therefore for...
  23. M

    Reflection from smartphone screen

    So here's a mystery one of you may be able to solve. I noticed that the reflection of light from the fingerprints on my iPhone screen depend on it's orientation toward a light source. For instance, use your finger to make two perpendicular smudges across the screen. You'll find that the smudge...
  24. Pushoam

    We see colour of an object due to reflection of light.

    Homework Statement How to demonstrate that we see colour of an object due to reflection of light? Homework EquationsThe Attempt at a Solution We see an object because photons from that object come to our eyes. The photons from the object comes to us due to radiation or reflection. If the...
  25. P

    I TIR (total internal reflection) in terms of quantum world

    how total internal reflection of light takes place in terms of quantum world?
  26. S

    Polarization of light and diffuse/specular reflection

    How would polarized light behave after being reflected by a diffuse surface, such as a white wall? Would it still be completely polarized or would it be more randomly polarized? Would whatever effect takes place vary significantly with different diffuse materials? What about a mirror? Surely...
  27. J

    How Do Color Differences Affect Wall Surface Temperatures?

    Hello, I would like to calculate the difference between a white surface wall surface and the same kind of wall but with brown outer surface. I would like to know the reflection and absorption indices and then calculate the surface temperature of the wall in the two solutions at the same...
  28. I

    Light reflecting through a geometry

    I am discussing physics with a friend and we need someone to confirm a thing that we're not agreeing on. We are discussing incident light that is passing through different geometries, and I want to know how the light behaves when it reflects inside a half sphere (of glass for example). Maybe...
  29. Const@ntine

    Maximizing and Minimizing Wavelength Contributions in Radiowave Reflection

    Homework Statement The transmitter is on the left, and the receiver is on the right. The transmitter transmits radiowaves. The distance between them is d = 50.0 m & each one's height is h = 35.0 m. The receiver can receive the radiowaves directly from the transmitter, or through reflection...
  30. M

    How does the use of a reflector affect the performance of a receive antenna?

    Do receivers only receive signals or they emit emf?
  31. A

    Is there any way to modulate/change a radio wave reflection?

    Hi all, Is there any way to impart a transformation upon a radio wave's reflection from an object, such that the reflected wave is different from the original signal in some way (frequency, phase, etc.)? Not sure what this would require (maybe a constant and active coordinated interference...
  32. M

    MHB When does a reflection around a point result in a reflection along a line?

    Hey! :o I am looking the following: For each point $Z$ let $\delta_Z$ be a reflection around the point $Z$. For which points $Z$ is $\sigma_g\circ\delta_Z$ a refection along a line, where $\sigma_g$ is the reflection along the line $2x+3y+4=0$? I have done the following: A reflection...
  33. D

    Multiple reflections and transmissions of light inside a cube

    Imagine I have a 10x10x10cm cube filled with a scintillating material (material capable of generating light when energized). Three cameras are looking at this cube from three orthogonal directions (x, y, and z). Light is generated inside the cube and is refracted as it leaves the cube and...
  34. M

    MHB How can we determine the reflection across a given line in Hesse normal form?

    Hey! :o Let $g$ be a line with equation $g:ax+by+c=0$ in Hesse normal form. I want to show that the reflection across $g$ is described by \begin{equation*}\binom{x}{y}\mapsto \binom{x}{y}-2(ax+by+c)\binom{a}{b}\end{equation*} At the reflection across $g$ it holds the following for the image...
  35. shihab-kol

    Rainy Day: Black Clouds and Light

    During a rainy day the clouds appear black but not so normally (in good climatic conditions) I think its something to do with light so I posted this query . If its not, sorry.
  36. shihab-kol

    Optics:Plane mirror and inverted image

    So,does a plane mirror(or a group of plane mirrors) ever form an inverted i.e. upside down image ? According to my own understanding, no. But in our home work this question was asked. So, is it possible??
  37. Andy_K

    B Double Slit Experiment: Timing & Reflection Interference

    Dear All, I have a couple questions on the double slit experiment I hope you can help shed some light (or photons) on. =) Arrival Timing of Photons In a normal double-slit experiment like the above setup, do photons always arrive at the detector at a constant speed (basically, speed of light)...
  38. shihab-kol

    The tangent and perpendicular of a mirror

    The tangent passes through just one point Now i can draw it such that the angle of incidence is always 0 and incident angle is always 90 Then no image will be formed. Why does this not happen??
  39. shihab-kol

    Centre of curvature of a mirror and the perpendicular

    If the normal is always 90 to the mirror can we assume that it always passes through centre of curvature? The light rays passing through the centre are reflected back in the same direction as angle of incidence is 0 and incident angle is 90 so, the normal should pass through the centre.
  40. Biniamin Piash

    Metal platings on glass and reflection in a mirror

    Which metal platings on glass will provide 100% reflection as a mirror? In which case we will get an brighter image than the actual one in mirror?And in which case it will be darker?Which metal(used for platings) will absorb a very little amount of ray? Can anyone give the explanation?
  41. Asamad

    Sun ray brightness quality after mirror reflection

    What is the Sun ray brightness quality after mirror reflection and what affects it? How to get the efficiency after reflection?
  42. T

    How does Total Internal Reflection in a mm/sm fiber work?

    I know Snell's Law and I do understand that there are single and multimode fibers. A fiber carries light hence to total internal reflection. so far so good. But is it only a single mode fibre that works with total internal reflection? And if so, how does the multimode fibre carry light then?
  43. J

    Coating Eyeglass Lenses(destructive interference)

    Homework Statement Eyeglass lenses can be coated on the inner surfaces to reduce the reflection of stray light to the eye. If the lenses are medium flint glass of refractive index 1.62 and the coating is fluorite of refractive index 1.432, (a) what minimum thickness of film is needed on the...
  44. Q

    Angular spread of light rays passing through a prism

    Homework Statement The problem asks: The index of refraction for violet light in silica flint glass is 1.66, and the index of refraction for red light is 1.62. What is the angular spread of visible light passing through a prism of apex angle 60 degrees if the angle of incidence is 50.03...
  45. Z

    Reflection of triangle over a line

    Homework Statement How to rotate a triangle over a line? I have provided a attachment for it? Homework Equations Y= mx +c I don't know the eq for reflection The Attempt at a Solution My plan is find the eq of line. I have got points for the end points of the line but i don't know how to...
  46. I

    Placing object between 2 spherical mirrors

    Homework Statement A concave mirror (f1 = 13.6 cm) and a convex mirror (f2 = −7.00 cm) are facing each other and are separated by a distance of 35.8 cm. An object is placed between the mirrors and is 17.9 cm from each mirror. Consider the light from the object that reflects first from the...
  47. T

    Energy Loss During Total Internal Reflection

    When a laser beam reflects during total internal reflection, how much of its intensity is lost? I can't the use Fresnel equations as this is for total internal reflection.If you don't know the answer to the above question, what about the same question, but for mirrors instead? What are the...
  48. C

    Exploring the Elusive Nature of Ghostly Entities in Scientific Research

    Does my mirror reflection have mass? What about your shadow?
  49. Docdan6

    Classical behavior, 3 dimension wave function and reflection

    Homework Statement I'm a pharmacologist and I have a modern physics course to do. This is not my field and I'm completely lost... We were given this problem to do. Thanks a lot in advance. Consider a potential where U(x) = 0 for x ≤ 0 U(x) = -3E for x > 0 Consider a particle of energy E...
  50. Toby_phys

    Mechanical wave reflection at a boundary

    Homework Statement Homework Equations The right hand section (A) has an incident and reflected wave $$y_1=Ae^{i(kx+\omega t)} +A'e^{i(-kx+\omega t)} $$ The middle section (B) has a transmission reflected wave $$y_2=Be^{i(k_2x+\omega t)} +B'e^{i(-k_2x+\omega t)}$$ Section (C) just has the...
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