Reflection Definition and 76 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. Ahmed1029

    I Reflection, refraction, and Snell's law

    Where do the laws of reflection, refraction, and Snell's law come from in geometric optics? Are they derivable from basic laws of physics?
  2. OliverFroelich

    A Iphone Reflection has a pattern

    Hi all! I'm sitting in the office on what would normally be a dive day so I'm slightly over observant. The sun is coming in heavy through my window, and holding my iPhone I began playing with the reflection on my office wall it produced. The reflection at first was no different then any light...
  3. hagopbul

    I I have a question about the mathematical model of a reflective curve

    Hello : Have a question regarding the mathematical model of reflective curve where could i find information on it ? (pdf , webpages , ebooks ,...etc ) Other than Wikipedia Best Regards HB
  4. Dom Tesilbirth

    The magnetic phase change of an electromagnetic wave during reflection

    If the question had mentioned ##\overrightarrow{E}## instead of ##E_\bot##, then we could have used ##\overrightarrow{B}=\dfrac{1}{v}\widehat{k}\times \overrightarrow{E}## to get the direction of the magnetic field. But the question had only mentioned ##E_\bot##. To my understanding, knowing...
  5. kuruman

    B Reflections on Reflection

    For quite some time I was under the mistaken impression that the specular reflection of objects from the calm surface of still water forms an image that is the same as the image I see except it's upside down. That is not the case. In the picture below* I have circled in white a couple of...
  6. Mr_Allod

    EM Wave Reflection and Transmission Between 3 Materials

    Hello there. I set up the problem like this, I have a wave incident from air on the anti-reflective coating consisting of: ##\tilde {\vec E_I} (z,t) = \tilde E_{0_I} e^{i(k_1z- \omega t)} \hat x## ##\tilde {\vec B_I} (z,t) = \frac 1 v \tilde E_{0_I} e^{i(k_1z- \omega t)} \hat y## This wave gets...
  7. Vivek98phyboy

    Reflection of inverted waves to form a standing wave

    Standing waves in a string fixed at one end is formed by incoming and reflected waves. If reflected waves are 180° out of phase with incoming wave, how could they combine to give an oscillating wave? Shouldn't it be completely destructive interference all the time across the whole length of string?
  8. Vivek98phyboy

    Contradiction in Phase of reflected sound

    While studying the fundamentals of sound waves in organ pipe, I noted that the fact about phase of reflected waves is contradicting while referring multiple sources This book of mine describes the reflection from a rigid surface/closed end to be in phase Whereas this one describes the...
  9. Elbraido

    B Compressing Light

    Hi there Let’s consider a photon of wavelength λ is being reflected across of gap d meters. The photon is a reflected back and forth between the same points on two horizontal sheets that reflect 100% of the light. What happens when the distance is smaller than wavelength? Thanks
  10. Manasan3010

    Reflection of a photon by an atom

    I suppose the reason I am able to see myself in mirror and not in wood is the reflection off a mirror is specular whereas wood is diffuse. In reflective material(e.g: silver) when the photon hits the frontline atom, the atom's electrons absorbs the energy and release it back with tiny energy...
  11. jason3w

    Create a focused beam angle of LED light using reflection

    Summary: Will an external surface reflect light into a more focused beam without using a traditional lens? Hey guys. Just trying to focus the light coming from a 1watt LED light source. It's native beam angle is 130 degrees. I'm hoping to focus it to around 30 degrees. We are creating an...
  12. S

    B Phase shift in Mach-Zehnder interferometer

    I'm confused by the phase shifts in a Mach-Zehnder interferometer because I keep finding two different explanations. One explanation (for example, given on Wikipedia, but also elsewhere) states that on each reflection, the phase shift is 180 degrees, but only, if light is reflected from the...
  13. DPMF6973

    Index of refraction and wavelength

    The problem is multiple choice. A) refraction b) diffraction c) reflection d) dispersion An explanation would also be greatly appreciated!
  14. J

    How is light reflected?

    Simple question. Are photons reflected as is from a surface like a mirror, or is the reflecting surface atoms capturing the photons and re-emitting them?
  15. ccdani

    Transmission of blue light through ceramics and surface roughness effects

    Hey :) I measured the transmission of blue visible light (350-550nm) through lithiumdisilicate ceramics with an ulbricht ball and an spectrometer. The light source was a led dental curing unit (bluephase style). The light guide was positioned direct on the ceramics. Now I wanted to test...
  16. Amaterasu21

    I How can light have a wavelength or change direction in SR?

    Hi all, I have two questions about light in Special Relativity. (I'm going to pad these questions out with a few statements about my understanding of length contraction and time dilation, so you can see how I currently think about it and clear up any misconceptions if I've got the basic idea...
  17. N

    Optical Smoothest yet not specular metal or plastic sheets?

    I'll get into the details why I need this for below but first I'll explain what I'm looking for. I basically need a flat sheet of aluminum or any plastic in grey or black color that doesn't provide specular reflections, yet is smooth enough to not have any noticeable texture when looking with...
  18. R

    Reflected Light Beam

    Hello, I have a question or perhaps a few questions regarding light and mirrors. When we point light at a mirror, it gets reflected back. But we can see the point light (assuming that it is a laser for the sake of simplicity) at a surface opposite to the reflective surface of the mirror. What...
  19. T

    What's the amount of energy lost in Total Internal Reflection?

    In Total Internal Reflection, the beam can still lose some energy as it reflects off the boundary of the medium it is within. This isn't covered under the Fresnel equations. The energy loss is probably lost in the form of evanescent waves. I tried searching for the formulae describing the...
  20. C

    How polarizers reflect light

    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...
  21. 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?
  22. 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...
  23. Rodrigo Schmidt

    Wave reflection on a string

    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...
  24. 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...
  25. 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...
  26. 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...
  27. 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...
  28. shihab-kol

    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.
  29. 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??
  30. 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??
  31. 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.
  32. 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?
  33. 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?
  34. 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...
  35. 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...
  36. 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...
  37. S

    Reflected sunlight

    I read in a book about a man who saw the sun reflected off a distant object on a mountain some 73 miles away in clear visibility. He saw this on many occasions and always wondered what it could be. He states that he asked two of his friends who were going that way if they would check it out...
  38. M

    Shining light on a retreating object

    Homework Statement I came up with this thought experiment last night, but I'm not confident in my solution--mostly because I forgo the time values I thought would be necessary to complete it. A reflective object moves past a lamp at time T0 with constant (non-relativistic) velocity V...
  39. P

    I Reflection of a massive particle

    Is the reflection of a (massive) quantum particle from a mirrored surface considered a Lorentz Boost?? If it is non-collinear ?
  40. E

    Dielectric slab and angle of incidence

    Hello! Let's consider a plane wave represented by a ray, propagating in a 2D dielectric slab. It has a medium with refractive index n_1 as its core and a medium with refractive index n_2, n_2 < n_1, as its cladding. In order for this ray to represent a mode, it must satisfy two conditions: -...
  41. Cocoleia

    Thin film appears red, thickness of this part?

    Homework Statement A thin film of oil (n=1.5) is floating on top of water. When looking directly at this film, a large portion appears red (700nm). What is the thickness of the red part of the layer? Homework Equations The Attempt at a Solution Since n for oil > n for air, there will be a...
  42. S

    Applying Snell's Law Inside & Outside a Prism

    Homework Statement I'm having trouble / uncertainties about the third missing angle (from left to right) in the picture. The first angle of reflection was easy as it's just 34 degrees as well and I used snell's law rearranged to find the first angle of refraction as 13.36 degrees from the...
  43. L

    B What is this tool named?

    Hi! I'm doing a light research project and to have a refraction and reflection ( I don't know if it's like this in eglish) visual representation I came up with this photo. I don't know the name of this tool and also what is it made of? In my opinion is just a glass but I don't really know. Thanks!
  44. E

    Why water looks transparent while spray looks white?

    The water looks transparent, but when the water hit the stone, it looks as if it turns white? Why?
  45. RabbitWho

    Virtual image on the perpendicular

    Homework Statement The book ("Real World Physics") says A virtual image in a plane mirror is on the perpendicular from the object to the mirror Homework Equations I know that the normal line is perpendicular to the surface of the mirror And I know that the angle of the incidence and reflection...
  46. Coco Hwang

    Reflection in a Plane Mirror

    1) If the angle of incidence of a ray of light to mirror is 50 degrees, what is the angle of reflection from the mirror? 2) If the angle of incidence of a ray of light to a mirror is 20 degrees, what angle does the light ray make with the mirror when it reflects? 3) If a ray of light makes an...
  47. S

    Transmission of mechanical wave on two different ropes

    Homework Statement Two infinite ropes, rope 1 and rope 2, of same linear density ##\mu=0.1 kg/m## have the same tension ##T=100N## and lie on the same plane, one perpendicular to the other. The two ropes are connected in the origin. On one of the two branches of rope 1 an harmonic wave is...
  48. spareine

    Do soap bubbles reflect sound?

    Bats in my garden do not seem to notice soap bubbles. Do soap bubbles reflect sound?
  49. bananabandana

    Plane Wave at Barrier

    Homework Statement Sorry for the dull question. Problem is as shown/attached Homework Equations The waves in part ii) are traveling in a HIL dielectric of permittivity ##\epsilon_{r}## from ##0 <z<d## and then hit an ideal metal boundary at ##z=d##. The Attempt at a Solution I figure this...
  50. A

    Find the distance from the mirrors for 4 reflections

    Homework Statement Two plain mirrors are put parallelly and 20 cm from each other. A source of light is put between the mirrors, 5 cm away from one. Find the distance from the mirrors of 4 first reflections. Homework Equations a1=a2 The distance of the object from the mirror and the reflection...