Reflection Definition and 966 Threads

  1. H

    Lens Reflection: Does Light Bounce Off?

    When a passing through a lens,will there any reflection on the surface of it?
  2. S

    How Do I Solve Laser Reflection Using Vectors?

    Question link: http://gyazo.com/4d52ab2521e5b222241718ea1b7ccb08.png I have to solve this using vectors, not geometry My professor said the equation that's required is -v* = 2 proj v onto n - v and v* is reflected vector, so I don't really understand how to do this First off I don't...
  3. PsychonautQQ

    How Do You Calculate the Cube Edge of Iron Using Bragg's Law?

    Homework Statement The bragg angle for reflection from the (110) planes in bcc iron is 22 degree's for an x-ray of wavelength = 1.54 angstroms. Compute the cube edge for iron. Homework Equations 2dsinθ=nλ ? The Attempt at a Solution I feel woefully underprepared for this problem and...
  4. X

    Length of coaxial cable, based on signal reflection

    Homework Statement We measured the time between a signal source, and it's reflection coming back through our probe after going through an open-ended coaxial cable. My teacher told us this: the cable has a polyethylene insulator between central wire and the grounding web, which has a...
  5. U

    Total internal reflection for a long time

    Imagine a square prism made from some material with such an index of refraction and surrounded by a substance of such index of refraction so that light rays entering the prism and hitting one of the internal sides of the prism at an angle of incidence 45° experience total internal reflection...
  6. U

    What is the Relationship Between Impedance of Dielectric and Material?

    Homework Statement Part(a): Show relation between impedance of dielectric and impedance of material: Part (b): Show the ratio between reflected and incident amplitude is: Part (c): Three layers now from left: vacuum, dielectric 2 sandwiched inbetween, and dielectric 1. Part (d)...
  7. S

    [FDTD/Fotran] detected reflection near boundary but don't know why

    hi all, i have wrote codes for 2d fdtd in different permittivity (epsilon). in this code, cell size is 200 x 200, start with eps=1 from center, and different permittivity started at boundary (i1,i2) = (25,75) = (j1,j2), epsilon = 2. the problem is, when the wave propagates and approach...
  8. D

    PHYSICAL explanation of light reflection by metals

    Electric field of an electromagnetic wave incident on a metal accelerates free electrons, and these accelerating electrons then emit radiation opposite to the electric field of the wave, thus reducing the resultant amplitude in the forward direction. Radiation emitted in the backward direction...
  9. S

    Feynman on Reflection: Exploring Time & Direction

    I have been reading the explanation of reflection that Feynman provides in The strange theory of light and matter. There are two things I do not understand: a) How does he choose the directions of the little arrows below the diagram? I understand that each path is different in that it...
  10. S

    X-ray diffraction or reflection?

    In x-ray diffraction , even though its reflection is happening , we call this as x ray diffraction. why is it so?? i don't know whether it has been discussed previously here.
  11. E

    What is the maximum reflection angle in the Chandra X-ray telescope optics?

    Homework Statement Hi! I'm having a problem with one assignment and I would really need som help. The question is: The Chandra X-ray telescope is used for observations in the 0.1-10 keV range. Focal length is 10 m, max mirror radius is 0.6 m. What is the largest reflection angle in the...
  12. L

    Why does a change in impedance cause reflection?

    why does a change in impedance causes reflection? I know that R=(Z2-Z1)/(Z1+Z2), but what is it that makes the wave be reflected? thanks
  13. E

    What is the largest reflection angle in the Chandra X-ray telescope?

    Hi! I'm having a problem with one assignment and I would really need som help. The question is: The Chandra X-ray telescope is used for observations in the 0.1-10 keV range. Focal length is 10 m, max mirror radius is 0.6 m. What is the largest reflection angle in the optics (assuming...
  14. W

    On the clockwise rotation of the reflection coefficient with frequency

    It is well known that the evolution of the input reflection coefficient, ρ, of a LTI causal passive system with frequency, f, always presents a local clockwise rotation when plotted in cartesian axes (Re(ρ), Im(ρ)), e.g. in a Smith chart, as shown in the attached figure. It must appointed that...
  15. N

    How does photon react in reflection and refraction?

    I want to apologize first of i post at the wrong section, not very sure if this is the right place for this post. First question, does the photon get absorbed when it hit highly reflecting material like mirror ? What make them look so different from the other transparent object? And I just...
  16. hb20007

    F(-x) is a reflection over the y axis -f(x)

    f(-x) is a reflection over the y axis -f(x) is a reflection over the x axis Now, how do we represent a reflection over y=x?
  17. Z

    Understanding the Doppler Effect and Reflection in Motionless Media

    Hello everyone, Here is something I've discussed with some colleagues recently and that generated a lot of disagreement, so I wanted to bring the topic to Physics Forums to ask what is your understanding of the situations and wheter you agree with the "solution" I provide below or not. Imagine...
  18. G

    What is the Maximum Angle for Total Internal Reflection in a 30-60-90 Prism?

    Homework Statement Red light is incident in air on a 30o - 60o - 90 o prism as shown. The incident beam is directed at an angle of φ1 = 37.6o with respect to the horizontal and enters the prism at a height h = 26 cm above the base. The beam leaves the prism to the air at a distance d =...
  19. P

    Virtual boxes mirror reflection

    Homework Statement Finding lightpaths with given starting and ending points via one or more mirrors. In those kind of problems you try image someone pointing a laser with a very narrow beam at a certain direction to the mirror, so it will reach point B. For example: You are seeing a square...
  20. P

    A mirror reflection of a mirror reflection

    a mirror reflection Homework Statement Create a set-up, as shown in the Figure, consisting of two mirror tiles (A and B) and a bird face, facing to the right . Make sure the two mirrors are perpendicular to the table and parallel to each other. The situation shown is a front view of the...
  21. ShayanJ

    Details of total internal reflection

    Consider snell's law n_1 \sin{\theta_1}=n_2 \sin{\theta_2} ( n_1 and n_2 are real). We know that if n_2<n_1 , there exists an incident angle called critical angle that gives a refraction angle of ninety degrees i.e. \sin{\theta_c}=\frac{n_2}{n_1} . But if the incident angle is greater...
  22. A

    Exploring Total Internal Reflection: Why Does Light Path Through a 2nd Medium?

    Hi And Need Help The main Question is what happens to light and cause go into next medium as total internal reflection happens for incident angles higher than critical angle ? so the main question is why the light path throughout the second medium? We know when light travels from a medium...
  23. R

    Reflection and absorption in matte black vs. shiny black objects

    Hi, I'm confused about reflection and absorption in materials. Is glossiness of an object determined by roughness of its surface rather than its inability to absorb visible light? If there are dark-colored objects where one has a matte finish and the other has a glossy finish, does this mean...
  24. N

    Electric field Phase change upon rarer to denser reflection of an EM

    Can anyone please provide an intuitive explanation of why phase shift of 180 degrees occurs in the Electric Field of a EM wave,when reflected from an optically denser medium and also why the phase remains same on reflection from a denser to rarer medium? please try to explain on an atomic/sub...
  25. M

    Find angle required for total internal reflection of a beam of light

    Homework Statement An optical fiber consists of a glass core (index of refraction n1) surrounded by a coating (index of refration n2<n1). Suppose a beam of light enters the fiber from air at an angle θ with the fiber axis as shown in attached. (a) Show that the greatest possible value of θ...
  26. H

    Full reflection of wave function for E = V0

    I have seen discussions which suggests that there is no solution for the interval after the step in a step potential where E = V0. The set up is a potential step where E = V0, with an interval 1 defined as x < 0 before the step and an interval 2 as x > 0 after the step. Is the following...
  27. M

    Photonics Question - Laser and Total Internal Reflection

    Hello, this is my first post to this site. I had this idea a few nights ago, and I've been trying to wrap my head around it. Before I go ordering supplies to run some tests, I thought it would be worthwhile to gain some insight from you guys. Anyways, as you probably know, total internal...
  28. P

    What Forces Act on a Particle During Quantum Reflection?

    Hi folks, So everyone at some point studying QM deals with reflections from 1D finite potential wells using the TISE, but something that I never covered was how to talk about or calculate the forces involved in turning around that particle. I tried to work something out below, but I'm not...
  29. V

    Equation for object size relative to reflection?

    Homework Statement The situation below is based upon the image of an object in the presence of a sheet with a small hole and an object that reflects an image onto a screen when shined with a light. The problem is below: Write an equation that shows the relationship between the length of...
  30. V

    How Thick Should a Plastic Plate Be for Maximum Microwave Reflection?

    Homework Statement A plastic plate with refraction index of 1.5 is placed in the interior of a micro-wave oven which operates with a frequency of 2.5 x 10^9 Hz. If the micro-waves are perpendicular to the surface of the plate, what is the minimum thickness of the plate so that the maximum...
  31. A

    How does a photon reflect off a smooth surface?

    Hello, I was just reading optics and I thought that if photon doesn't has mass it can't be accelerated.. If it is so then how it gets reflected off a smooth surface, why don't it just passes from the plane. As any reaction force by the plane couldn't accelerate it , it mustn't rebond as...
  32. H

    Reflection of particles and light: different reflection surface types

    Hi, I'm interested in reflection of both particles and light off surfaces. My problem is associated with a model that I'm working on and can be divided into two parts as far as I see it. The first problem is the reflection of particles off the surface and the change in velocity due to...
  33. K

    Simple Transformation of a Function: translation, reflection, sketch

    Homework Statement Hi all. I am having trouble to understand the combination of transformation on a function: h(x)= a*f(b(x-c))+dHomework Equations The problem I am struggling with is the order of transformation; I do see that: f(x-c) is translation in the right since every event happen before...
  34. S

    Is Stefan–Boltzmann law valid for light reflection

    I know emissivity parameter of Stefan-Boltzmann equation is related to both "absorption" and "emission" of the material. But is it related to "reflection" property of an object? If not what is the parameter that makes an object shiny?
  35. I

    How does wave reflection work?

    this is a silly question but, how exactly does the reflection of a wave work? explain to me the mechanics/physics please. say you have a rope attached to a wall at one end. and at the other end there is a wave generator. a wave is generated and right when the wave front hits the wall, what...
  36. D

    Statistical physics reflection principle

    Homework Statement Consider a random walker in one dimension, which can take right or left steps with equal probability. Assume that the walker starts at the location k>0 and there is an absorbing wall at point labelled as 0, that means if the walker reaches 0 the process stops and he stays...
  37. A

    Total internal reflection inside a fiber optic cable

    Homework Statement A multi-mode fiber optic cable has a core diameter d = 115 mm, ncore = 1.42, and ncladding = 1.17. What is the largest possible angle θin relative to the surface normal that light can enter the fiber (i.e. pass from air into the fiber core) and experience total internal...
  38. Saitama

    Ray optics - Reflection from sphere

    Homework Statement A light ray parallel to the x-axis strikes the outer reflecting surface of a sphere at a point (2,2,0). Its center is at the point (0,0,-1). The unit vector along the direction of reflected ray is ##x\hat{i}+y\hat{j}+z\hat{k}##. Find the value of ##yz/x^2##. Homework...
  39. MikeGomez

    Does Quantum Mechanics Explain the Fuzziness in Light Reflection?

    From this video of a Feynman lecture: At 39:30 he (Feynman) draws a line from the eye to the mirror, and then continues the line through the mirror, to represent where the image appears to come from (it appears to come from behind the mirror). Here he is showing the classical way of...
  40. Y

    Help with vector calculus in reflection and transmission of plane wave

    This is not a homework, this is concerning reflection and transmission of electromagnetic wave ( plane wave) at a flat planar boundary between two media. But the work in question is pure vector calculus. I ultimately want to proof if ##\vec E_I=\hat y E_I## then ## \vec E_R## and ##\vec E_T##...
  41. jaumzaum

    Torque, Momentum and Reflection

    A light beam of frequency f hits a mirror of length L at a distance 3/4 L from one end, which is fixed but can rotate freely around the axis as shown. The mirror has mass m and can be considered a rectangular plate. The light beam hits (and fully reflects) the mirror at a rate of N photons per...
  42. Y

    Please check what's in the Ulaby book regarding reflection.

    Attached is a scanned of the page in question. This is regarding to Perpendicularly polarized plane wave. in equation (9.47a) at the lower left corner it is the distance ##x_i## to the origin. x_i=x\sin\theta_i+z\cos\theta_i\;\hbox {(9.47a)} That is not a distance. distance of ##|\vec...
  43. Y

    Question in reflection and transmission at oblique incidence.

    I am reading Griffiths p387. It is my understanding that \tilde E(\vec r,t)=\hat r E_0 e^{j(\omega t-kr)} Where ##\vec r =\hat x x+\hat y y+ \hat z z## is the positional vector from the origin to the observation point ( x,y,z). \Rightarrow\;\tilde E(\vec r,t)=\hat r E_0...
  44. Y

    Question of reflection and transmission of TEM wave in normal incidenc

    Suppose TEM wave in +z normal to a boundary on xy plane at z=0. We know E & H are tangential to the boundary. Let ##\vec E_i=\hat x E##, be the incident wave towards the boundary therefore incident H is ##\vec H_i =\hat z\times \hat x \frac {E_i}{η}=\hat y H##. I have a few questions: 1) How...
  45. J

    Any Conceptual Underpinning for Partial Reflection of Light (QED)

    Any Conceptual Underpinning for Partial Reflection of Light (QED)? I recently partially read Feynman's QED. At one point, he says "The situation today is, we haven't got a good model to explain partial reflection by two surfaces;..." (page 24--can visit Amazon "Look Inside" to read) My...
  46. W

    Calculate Reflected Radiance from Wave Facet

    When I view the sea surface for a few seconds (using a camera), some wave facets have very high radiance values. I understand that there is a distribution of slopes and that one can determine a statistical radiance distribution, but how do I calculated the reflected radiance from a single wave...
  47. S

    Polarization by reflection and Brewsters Angle

    Homework Statement A beam of light is reflected off the surface of some unknown liquid, and the light is examined with a linear sheet polarizer. It is found that when the central axis of the polarizer (that is, perpendicular to the plane of the sheet) is tilted down from the vertical at an...
  48. S

    Reflection of Light ~ Mirror on one side, surveillance on the other.

    Question In many department stores, large plane mirrors have been placed high on walls or on projections from ceilings. These may be one-way mirrors that are designed to allow one-way surveillance of the store. From one side, this surface looks like a mirror, but from the other side, the...
  49. P

    Δp for total reflection and absorbtion of E&M radiation explanation?

    The equation for the change in momentum for total absorption of electromagnetic radiation is ΔU/c and that for total reflection is (2ΔU)/c. How could the momentum of electromagnetic radiation change if it is massless and travels at a constant speed c? Is the ΔU just a representation of a change...
  50. 7

    Transmission and Reflection on a potential step

    Lets say we have a potential step with regions 1 with zero potential ##W_p\!=\!0## (this is a free particle) and region 2 with potential ##W_p##. Wave functions in this case are: \begin{align} \psi_1&=Ae^{i\mathcal L x} + B e^{-i\mathcal L x} & \mathcal L &\equiv \sqrt{\frac{2mW}{\hbar^2}}\\...
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