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. H

    The reflection of resonance tube

    any one knows why sound wave reflects at the opening end of the resonance tube? is the air inside the tube different from those outside. from the expriment, when the incident wave interference with the reflected one, the destructive point reachs almost zero showing that the reflected one has...
  2. Fernando Revilla

    MHB Theman123's question at Yahoo Answers (Rotation and reflection)

    Here is the question: Here is a link to the question: Let S: I have posted a link there to this topic so the OP can find my response.
  3. F

    Phase shift upon reflection of electromagnetic wave

    I have indirectly sought the answer to this for some time (since I studied an introductory course in optics 'long' ago), but nobody has been able to give a satisfactory answer, and I have not been able to find the exact answer on the Internet either. My question is about optics, and more...
  4. E

    Quantifying Light Reflection and Scatter in Chrome Paint: A Scientific Study

    Hello, I am think of using chrome paint to create a uniquely shaped mirror. I was wondering if anyone has done studies to quantify how much light is reflected from different types of chrome and how much the light scatter. I realize chrome paint isn't the same as chrome, but I couldn't find...
  5. H

    Why Does Bragg Diffraction Occur for Bound Electrons in a Crystal?

    As far as I know, Bragg diffraction happens for incident particles which are free; for example free electrons or X-ray are Bragg-reflected under the special conditions. Why the Bragg diffraction happens for electrons which are not free in a crystal?
  6. D

    How Can Fermat's Principle Prove the Second Law of Reflection?

    Hi, I am trying to prove the second law of reflection using fermat's principle and I am not entirely sure how to start it. By the way the second law of reflection is: The incident ray, reflect ray and normal ray all lie in a single plane.
  7. S

    Reflection and refraction of light

    Homework Statement One of the contests at the school carnival is to throw a spear at an underwater target lying flat on the bottom of a pool. The water is 0.900 m deep. You're standing on a small stool that places your eyes 3.20 m above the bottom of the pool. As you look at the target, your...
  8. F

    How to Determine the Refractive Index of Glass Using Polarized Light?

    Homework Statement Unpolarized light falls on an angle of 37.5 ° with a plan glass surface. The reflected light polarization is examined with a Polaroid. The ratio between maximum and minimum intensity from Polaroid when it is rotated around is 4.0. Which is the refractive of index glass...
  9. F

    How Does Polarization by Reflection Determine the Refractive Index of Glass?

    Unpolarized light falls on an angle of 37.5 ° with a plan glass surface. The reflected light polarization is examined with a Polaroid. The ratio between maximum and minimum intensity from Polaroid when it is rotated around is 4.0. Which is the refractive of index glass? I would like to use the...
  10. H

    Difference between Frensel reflection and Total Internal Reflection

    What exactly is the difference between Frensel reflection and total internal reflection with regards to the efficiency of an LED? Do they both occur at the semiconductor/ air interface? I am a bit confused, thanks for the help.
  11. C

    Calculating Heat Reflection with a Radiometer: Mass/Force Equation

    using a radiometer reference, what is the equation to the force or mass of the heat reflecting of a specified surface area.
  12. A

    Transverse Wave in a String Reflection and Transmission

    A string with a density/length of rho and tension T has an elastic spring with stiffness k at x=0. There is a step pulse (fi = H(t)) incident on this discontinuity. Determine the reflected and transmitted waves. Im not sure what boundary condition to use at the location of the spring. All...
  13. K

    Regarding transmission and reflection of EM-waves

    Hello! I´m trying to read Jacksons 'Classical Electrodynamics' and solving some problems. At the moment I´m stuck at problem 7.3. I started looking at suggested solutions (http://www-personal.umich.edu/~pran/jackson/P505/F07_hw11a.pdf) but I need some help I guess. Looking at how other people...
  14. B

    Calculating Reflection angle in a 2D plane.

    Im trying to calculate the refelction angle of 2 points in a 2d plane, but not the same distance away from the reflection surface, and I'm drawing a blank. Any help would be hugely appreciated.
  15. A

    Why frequency stays the same during transmission and reflection

    Why does frequency of a wave stay the same during transmission and reflection?
  16. P

    Light reflection without a surface

    Hello everyone, this is my first post so bare with me... I was searching the internet for light reflection and all other properties of light.Since we all know light requires a surface to reflect so that we see the objects. Can we reflect the light in space without requiring a surface?
  17. T

    Teeth double reflection in mirrors

    Hello, guys! Yesterday I saw my reflection in a mirror and noticed that my teeth had two images on the mirror, and the rest of my face did not. I tried in different mirrors, and the result was the same. At first, I thought it could be the effect of two surfaces of the mirror, and in that case...
  18. R

    Does dispersion of light occur in reflection?

    During refraction the different colors that white light is composed of are dispersed but does this happen during reflection or total internal reflection?
  19. R

    Refraction: Reflection after passing the critical angle

    If the angle of incidence is greater than the critical angle then it is reflected back into same medium. Is this reflection normal reflection? (as in it obeys all the rules of reflection, like reflection in mirrors) Or is it a bit different?
  20. S

    Qualitative Description of Reflection

    Hi, I was hoping someone could provide a good qualitative description of how metals reflect light, preferably with reference. From my understanding, metals reflect low frequency light quite well. I believe the mechanism is that the light oscillates the electron back and forth. Q1...
  21. S

    Reflection Grating: Exploring The Wavelength Dependence

    hi, I am bothered by some question for a long time. From basic optics, i know that the the angle of incidence equals the angle of reflection [where we define the incident angle as the angle between the beam and the normal to the surface of course]. What I can't understand is why when a...
  22. S

    Do Reflection Questions Enhance Understanding of Optics Problems?

    Homework Statement Im having problems with these questions i just can't seem to get them Any help would be good thank you in advance 1. An object located 40cm in front of a mirror produces an erect image 80cm from the mirror. Find the radius of curvature for the mirror, and state the...
  23. S

    Calculating Direction of Specular Reflected Sun Beam

    Homework Statement Given the position of the sun (zenith and azimuth angle) and the orientation of a plane (inclination angle and orientation angle). What would be the correct equation to calculate the direction (zenith and azimuth angle) of the specular reflected sun beam as seen from that...
  24. R

    Reflection in spherical mirrors

    Hey everyone, I'm reading a chapter on reflection of Light and I had some doubts:- 1 Is a real, erect image possible? What about a virtual, inverted image? 2 How can you see a real image without a screen? Can you see it in the air or something? 3 When you move away from a plane mirror...
  25. S

    Light Reflection and Feynmans plane of oscillating charges

    In ch 30-7 of the Lectures, Feynman explains that the field of a plane of oscillating charges at a point P is proportional to the velocity of the charges, considered at the appropriate retarded time (retarded by the vertical distance from the point P). Feynman derives this formula only for...
  26. M

    QED, partial reflection, Feynman, FTL

    I would like to discuss partial reflection of the photons and how thickness of the material (let's say glass) affects reflection (originally from Feynman, QED). Let's say we have a glass 1m apart from the detector, and another glass 100m apart. The thickness of second glass affects probability...
  27. B

    Optics, Minimizing Reflection with Refraction Index Numbers HELP?

    Homework Statement What is the minimum thickness of coating which should be placed on a lens in order to minimize reflection of 401 nm light? The index of refraction of the coating material is 1.31 and the index of the glass is 1.56. Homework Equations I haven't been able to attempt the...
  28. R

    Polarization of Light After Reflection from Surfaces

    I was wondering what happens with linearly polarized light when it is reflected from a surface such as paper? Since it undergoes diffuse reflection, it is scattered in all directions, but does it become randomly polarized, as well? I can't really find an answer to that anywhere, so I'd be...
  29. X

    Calculating Reflection Angle and Frequency for Moving Mirror?

    Homework Statement A mirror is moving uniformly in a direction normal to its plane with velocity v=βc. Given the angle of incidence and frequency of an incident photon (θ_e,nu_e in the figure), calculate the reflection angle and the observed new frequency (θ_i,nu_i in the figure). Also...
  30. V

    Rebuilding Math Foundations: Reflection on a Late Start

    The short summary is that my high school foundations of math were absolutely terrible as I was instructed from the youngest age that mathematics was entirely about computation and that being talented in math meant being able to handle lots of number grinding in your head without a calculator. I...
  31. J

    Efficient 3D Vector Reflection: Simplifying Unknowns in Mirror Systems

    Hello All, Let say I have a system of two planar mirrors (M1 and M2), with a known input (I), and a desired output (O2). Here are the parameters: Azimuth of input: A Polar of input: B Azimuth of normal of M1: A+180 Polar of normal of M1: X1 (unknown) Azimuth of reflected ray from M1: A+180...
  32. M

    Laplace equation charge reflection

    Homework Statement Show that If \phi(x,y,z) is a solution of Laplace's equation, show that \frac{1}{r}\phi (\frac{x}{r^2} ,\frac{y}{r^2} , \frac{z}{r^2} ) is also a solution Homework Equations The Attempt at a Solution let \psi= \frac{1}{r} \phi (\frac{x}{r^2}...
  33. 2

    How does the reflection of light work?

    Hello. How does light get reflected? Do photons act like balls which bounce off a surface? If I shoot a single photon which has a frequency of an orange color, and that photon hits a tomato, it should get absorbed, right? What if it hits an orange? Will it bounce off an atom? How does that...
  34. S

    Photonics: Ray Reflection Question

    The question can be found at this link: http://gyazo.com/ee82873af32d76898ab1c5b9f058a2eb My reasoning for part A follows as such: Because the radius of curvature is smaller in the second mirror than in the initial elliptical mirror, every point on the second mirror (other than the tangent...
  35. A

    Interference by amplitude division (double reflection) for wedges

    Homework Statement Transparent wax of refractive index n=1.3 is deposited on top of a glass plate of width 1cm and refractive index n=1.5. The thickness of the wax is 0.01mm at one end of the plate and tapers uniformly to zero at the other end of the plate, which is defined to be at x=0. At...
  36. F

    Finding the matrix for a reflection about a plane in R^3

    Homework Statement Let L: R^3 -> R^3 be the linear transformation that is defined by the reflection about the plane P: 2x + y -2z = 0 in R^3. Namely, L(u) = u if u is the vector that lies in the plane P; and L(u) = -u if u is a vector perpendicular to the plane P. Find an orthonormal basis for...
  37. H

    What precisely IS reflection: what happens at the microscopic level?

    I post in the QM section as an answer in terms of photons rather than just EM waves would be better.
  38. S

    Total Internal Reflection and snell's law

    When we talk about Snell's law, and total internal reflection in particular, we usually will draw diagrams as if light is coming off a point in a single, straight line (that bends at an interface, of course). My question is, though, how does this light behave when it's coming off an extended...
  39. cryora

    At the subatomic level, how does reflection and refraction occur?

    I'm guessing it has to do with electron excitation, and the release of EM waves when the electrons fall back to their ground state, but I am want to learn more about this in detail. I've barely covered Maxwell's Equations and optics in a lower division general physics course, so there's a whole...
  40. Drakkith

    Does total internal reflection only occur with electromagnetic waves?

    Does total internal reflection happen with all types of waves, or just electromagnetic ones?
  41. C

    Line of Polarizers Reflection Question

    http://plc.cwru.edu/tutorial/enhanced/files/lc/phase/Graphics%5Cschem.BMP I was hoping someone could help me with understanding why a row of polarizes reflects a light wave when the whole row (the pitch P) is the same length as the wavelength of the light...
  42. A

    Does Fresnel reflection involves absorption of light?

    When a ray interacts with a solid if the surface is polished reflection occurs. This is true even if the material absorbs at the specific wave lenght? In other words if the material absorbs at the specific λ, can occurs Fresnel reflection ? Or: Fresnel reflection has always all the same λs of...
  43. J

    Glass that has minimum reflection and absorption at 1550nm

    I am building an enclosure for my laser that emits at 1550nm. I need to integrate a window for the laser light to pass through. Anybody have any recommendations on what kind of glass would work best so that the optical losses are kept at a minimum? Ideally, it would be commercially available...
  44. A

    Total Internal Reflection a doubt?

    I was reading about a case of total internal reflection in mirrors and something got me curious... Is there anything such as 'weak refractions'?? In the diagram of the mirror I saw, as a ray of light from an object entered a mirror, it was reflected by the silver coating, and then by the...
  45. S

    Water waves - is this reflection, or refraction, or both?

    http://img42.imageshack.us/img42/9712/refractionk.jpg Now my understanding is that water slows down when it goes over a shallow area because the ground under the shallow water is interfering with the wave. When this happens the wave becomes more transverse which I guess is due to reflection as...
  46. cryora

    Wave Optics (Interference due to reflection)

    Homework Statement A radio-wave transmitter and a receiver, separated by a distance d = 50.0m, are both h = 35.0m above the ground. The receiver can receive signals directly from the transmitter and indirectly from signals that reflect from the ground. Assume the ground is level between the...
  47. P

    Does Light Reflect at the Boundary Between Water and Flint Glass?

    Homework Statement At the boundary between water (n=1.33) and flint glass (n=1.66), incoming light at ~49 degrees from the normal is refracted. Of course, I can use Snell's law to calculate the angle of refraction. However, my question is whether any of the light at this boundary is also...
  48. K

    Total Reflection of a Classical Particle off a Two-Dimensional Potential

    Homework Statement This question is motivated by Problem 8, Ch 1 of Cohen-Tannoudji's "Quantum Mechanics". Suppose that you are given a two dimensional potential of the form V(x,y) = V if x>0 and V(x,y)=0 if x<0. A particle travels toward the the potential obliquely, i.e. neither parallel to...
  49. J

    Help~total internal reflection

    can anyone explain for me :)? I have no idea:(
  50. S

    The relationship between absorbtion, emissivity and reflection

    As I understand it, the absorption coefficient of a surface of material is the same as its emissivity (due to Kirchoff's law of thermal radiation), and that the net of this and the tranmissibility is emissivity + reflectivity + transmissibility = 1 Is this a general statement about...
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