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. D

    Specular Reflection for 3-D Particle Collision

    I am writing code for a particle simulation and I have this question: Homework Statement A particle, with initial coordinates (xi,yi,zi) w.r.t a fixed origin in a global rectangular coordinate system, is traveling toward one of the faces of a cube with a speed whose direction can be described...
  2. K

    How Does Light Behave When It Strikes a Glass Plate?

    Homework Statement A light ray in air is incident on a glass plate whose index of refraction is 1.42. The angle of refraction (transmitted angle) is one-half the angle of reflection. (Take the index of refraction in air to = 1.00). A) Relative to the normal to the plate’s surface, what...
  3. E

    Electromagnetic Reflection and Refraction

    Homework Statement An EM wave travels in vacuum and incidents on a dialectric material in the XZ plane. The wave's polarization is in the \hat{y} direction. Prove that the polarization of both reflected and refracted waves are too along the \hat{y} axis. Homework Equations The...
  4. V

    Charge & Reflection: Explaining What It Means

    The Amasci site makes this statement: "charge is the stuff that reflects light and makes objects visible..." Can anyone elaborate on what this means? I cannot think of a way to explain it at all - I don't even understand how charges could reflect light. Thanks!
  5. S

    Question about law of reflection

    When is the law "the image is formed back in the mirror at a distance equal to that of the object from the mirror applicable? Consider a plane mirror,with a glass slab on it. Let an object be placed in front of it outside the slab, in air. Now due to normal shift the mirror will see the...
  6. jegues

    Total Internal Reflection Confusion

    Homework Statement See figure attached. Homework Equations The Attempt at a Solution Initially, \theta_{c} = 60^{o} n_{glass}sin\theta_{c} = n_{air} So, n_{glass} = \frac{n_{air}}{sin\theta_{c}} Now I would think that the incident angle from glass to air would be...
  7. genxium

    Engineering How can I understand reflection coefficient for a certain circuit?

    How can I understand "reflection coefficient" for a certain circuit? Homework Statement I'm a beginner in RF circuit, though I've learned something about low frequency oscillator design, some new concepts still confuse me a lot, like the "reflection coefficient". I google it and found...
  8. M

    Calculating Relative Phase of Reflected Plane Waves in Lossless Materials

    not relating to any specific homework question: how can i go about calculating the relative phase of reflected / transmitted fields for normally incident plane waves? for example, i know how to calculate the relative amplitude of the reflected field from the reflection coefficient...
  9. P

    Why don't metals polarize light on reflection

    I know that dielectrics polarize light reflected at/near the Brewster angle, but why is it that metals never do this, only dielectrics? Also, does anyone know of a good, simple conceptual explanation for why light becomes polarized when it's reflected from dielectrics?
  10. F

    Problem in reflection from half-infinite magnetic media

    1.A linearly polarized plane wave, traveling in vacuum in the x-direction, is incident on a half-infinite magnetic region. The magnetic material is magnetized in the +y-direction with the saturation magnetization Ms . The dc magnetic field inside this material (internal dc field) is constant...
  11. A

    Is There a Disagreement on Wave Reflection in Different Sources?

    Please look at the two sources that describe wave reflection. Hyperphysics states that when a wave meets a rigid surface, it changes phase by 180 deg, such that an upright wave will reflect upright, as to produce a standing wave with the right conditions...
  12. S

    Problem with reflection and refraction.

    1. A 1 cm tall object sits 6cm to the left of a converging lens, f = 10 cm. A flat plane mirror sits 2 cm to the right of the lens. Light passes through the lens, reflects off the mirror, then back through the lens. Where is the final image? Real or Virtual? Upright or inverted? How big is it...
  13. K

    Mirror Image Distance: Exploring the Law of Reflection

    Homework Statement How far behind the mirror is the image of an object that is located in front of a flat (plane) mirror? Why do you think the image produced by a flat (plane) mirror is called a virtual image Homework Equations The Attempt at a Solution
  14. JJBladester

    Reflection from a plane mirror

    Homework Statement You need to place a mirror on the left wall of the figure so that the reflected light from the bulb exactly fills the right wall. A) What is the proper height of the mirror? B) How far below the ceiling should the top edge of the mirror be? Homework Equations...
  15. B

    Calculate Reflection & Transmission of Candle Flame Images in Glass Sphere

    A fortune-teller’s crystal ball is a sphere of diameter 200 mm, made of glass with refractive index 1.70. A candle flame of height 10 mm is placed 1.00 metre away from the surface of the ball. Calculate the position and size of the two images of the flame: (i) reflected in the ball’s...
  16. J

    Is Huygens' Principle of Reflection Incomplete?

    The incompleteness of Huygens principle has been discussed at length here and elsewhere, and has actually been completed, regarding wave propagation and refraction, relatively shortly afterwards (by Kirchhoff and Fresnel). This post is specifically about reflection, and should you be familiar...
  17. S

    Reflection of light with known refractive index.

    This is for my 1st year undergrad course but it feels quite basic and not worthy of the 'Advanced Physics' section. Yet there's one thing I'm confused about - I have the answer, just something I don't understand. Homework Statement Light falls normally on a glass surface. What fraction of the...
  18. Z

    How Is the Value of k Determined in Refraction and Reflection Problems?

    Homework Statement A point object is placed at distance of 40 cm from a composite refracting slab whose one face is silvered as shown. The separation between the object and its final image is (100 – k)cm. Find the value of k. The Attempt at a Solution I got the separation as...
  19. G

    Transmission and reflection for olique incidence at a uniform dielectric slab

    1. Homework Statement A di-electric slab of thickness d is between two differing dielectric media (u0,e0/u1,e1/u2,e2). What is the total reflection at the first interface and transmission through the second interface of the slab. The incident wave is in the x-z plane with an angle of...
  20. jegues

    What is the Minimum Refractive Index for Total Internal Reflection?

    Homework Statement See figure attached for problem statement. Homework Equations The Attempt at a Solution Using Snell's Law, n_{1}sin(\theta_{1}) = n_{2}sin(\theta_{2}) n_{1} = \frac{n_{2}sin(\theta_{2})}{sin(\theta_{1})} Where, \theta_{1} = 30^{o}, \theta_{2} =...
  21. Q

    Solving the Car's Speed: Radar Velocity and Reflection

    Homework Statement A car is driving west and a patrol officer is driving east at 23.50 m/s. The officer's radar gun indicates that the car is speeding. If the radar gun sends out a frequency of 24.15GHz and receives a reflected signal of 24.20GHz, what is the velocity of the car? (Assume radar...
  22. C

    Find the Optimal Film Thickness for Yellow and Purple Light Reflection

    Homework Statement A client has asked you to produce a sheet of material that will appear yellow for transmitted light and purple for reflected light. You decide that "yellow light" is 600 nm and that "purple light" is 400 nm. If you use MgF2 (n2= 1.39), how think should the sheet be...
  23. K

    Total internal reflection zero

    How is that in refraction of light energy is lost but not in case of total internal reflection? Is the loss in total internal reflection exactly zero?
  24. B

    Losses involved in reflection and refraction

    when light is reflected on a surface, there is always going to be some absorbsion by the reflective material. what I'm curious to find out is whether the losses in refraction are compareable? is it just dependant on the transparency of the material?
  25. D

    How Do You Calculate Cylinder Rotation Using Laser Reflection?

    Homework Statement You're helping with an experiment in which a vertical cylinder will rotate about its axis by a very small angle. You need to devise a way to measure this angle. You decide to use what is called an optical lever. You begin by mounting a small mirror on top of the cylinder. A...
  26. P

    Finding a Basis for a Reflection in R^2

    Find a basis Beta in R^2 such that the beta matrix B of the given linear transformation T is diagonal. The Reflection T about the line R^2 spanned by [1 2], [1 2] is suppose to be verticle. B=S^-1AS or B=[[T(v1)]beta [T(v20]beta] so i found the reflection matrix to be...
  27. A

    Reflection of a Wave: Amplitude, Frequency, Velocity

    Homework Statement 1. When a wave is reflected from a mirror, there is no change in its a) Amplitude b) Frequency c) Velocity d) All Homework Equations The Attempt at a Solution I think frequency changes,not sure
  28. M

    Reflection coefficient (osmosis)

    hello ppl, i have a question about the reflection coefficient... since the RC indicates the permeabilty of a membrane for a specific molecule...doesnt that mean (If the RC between 0 and 1) that the concentration of that molecule on both sides of the membrane will become the same after a while...
  29. J

    The process involved in reflection?

    when we have light reflecting off a material, what's going on there? is it something analogous to a gas particle rebounding off a container wall due to Coulomb repulsion? If so, what is it that exerts a force to reverse the photon's momentum perpendicular to the surface it's reflecting off...
  30. A

    Struggling with Total Internal Reflection? Need Help for Exam Prep?

    Homework Statement Hi I wonder if anyone can help. I am having difficulty drawing refracted and total internally reflected rays. I have an exam on Monday. Can anybody recommend good websites that can help? Slight panic. Thanks Homework Equations The Attempt at a Solution
  31. N

    Light Reflection: Does Electric Source Affect Places A, B & C?

    If light is from electric source, would persons on places A, B and C register any light in any spectrum.
  32. M

    Total Internal reflection is Glass Prism Question

    Question about Total Internal Reflection? My textbook says that for total internal reflection to occur 2 conditions need to be met. Light is traveling more slowly in the first medium than the second medium and no.2 is the angle of incidence must be large enough for no refraction to occur. My...
  33. M

    Total Internal Reflection in Glass prism Question?

    Question about Total Internal Reflection? My textbook says that for total internal reflection to occur 2 conditions need to be met. Light is traveling more slowly in the first medium than the second medium and no.2 is the angle of incidence must be large enough for no refraction to occur. My...
  34. V

    Reflection of light through a wine glass with water

    Hello, I came across something interesting on the internet. I saw an image in which a wine glass was half filled with water and put in the middle of the two different colored backgrounds. In the air portion within the glass, the two backgrounds were visible through the glass, however; in the...
  35. A

    Light reflection from edge of universe

    tif we presume that our finite universe has a boundry. This boundry is due to the pull of gravity. Light will slow down and then come back to us. 'i may be absolutely wrong in this'. My question is that the light we see will be from the stars surface that doesn't face us and star moving away...
  36. Z

    Pulleys + Convex Mirror Reflection

    Homework Statement In the given arrangement pulley P1 and P2 are moving with constant speed vo downward and the centre of the pulley P lies on the principal axis of a convex mirror having radius of curvature R. Find the speed of image of pulley P when it is at a distance x from the surface...
  37. H

    Reflection of Waves: Is the Pulse Inverted?

    A pulse reaches the boundary of a medium in which the speed of the pulse becomes higher. Is the reflection of the pulse the same as for the incident pulse or is it inverted? Also, does pulse refer only to mechanical waves and not to electromagnetic waves?
  38. H

    What is the angle of incidence and reflection when facing a plain mirror?

    What is the law of reflection to the object, when it's perpendicular to the reflective surface. For example, if you face a mirror and stare eye to eye with the reflection- what is the angle?If I have understood correctly, the angle of incidence/reflection is equal, so if for the mirror is...
  39. D

    Refraction and Reflection of light

    7. (a) A material having an index of refraction n = 1.30 is used as an antireflective coating on glass with an index of refraction n = 1.50 as shown. (i) What is the phase shift for the reflection at the interface between air and the coating (interface 1)? (ii) What is the phase shift...
  40. E

    Light absorption and reflection

    Hi there! I have a question about the classical interaction of light with matter according the Drude-Lorentz model. Let's suppose that the light in matter has a wave-number k which in general is complex. Then the real part of k accounts for the propagation of light, while the imaginary part of...
  41. L

    Transmission, reflection, and absorbtion

    In order for us to see something, the light photon needs to be reflected, not absorbed or transmitted? Then is it that the same frequency of visible light keeps falling on something, an apple is always red in white light, why does it reflect red?
  42. D

    Lambert's Cosine Law, Computing Diffuse Reflection

    Lambert's Cosine Law, Computing Diffuse Reflection : I have 2 coordinates (5, 6, 0) the light source and (2.3, 1.92, 0) the plane. The diffuse coefficient is 0.6 and the light source intensity is 200. So using the Lambert's Cosine Law, I need to take 0.6 * 200 * the dot product of the...
  43. S

    Total internal reflection mirror?

    Hi all, From what I understand, total internal reflection reflect 100% of light. Suppose you had a transparent material with a critical angle of 45 degrees. Now say you had a cone with a 45 degree angle, and you shined monochromatic light in through the base. Would 100% be reflected (minus...
  44. I

    Find Basis of R^n for Diagonal B Matrix of Reflection T in R^3

    Homework Statement Find a basis B of R^n such that the B matrix B of the given linear transformation T is diagonal. Reflection T about the plane x_1 - 2x_2 + 2x_3 = 0 in R^3. The Attempt at a Solution I just don't even know where to begin. I don't know how to interpret problem or how to...
  45. A

    Heat absorption, reflection, and radiation

    Homework Statement 1.if you were to paint a house that reflects heat during summer and radiates heat during winter nights. which color should a house be painted? green, red, black, white, or pink? 2. why do gardeners mix soot in the soil? The Attempt at a Solution 1.i say it is...
  46. F

    Diffuse Reflection: How is it Computed?

    I'm confused as to how the diffuse reflection is computed as : \frac{1} {\pi} * LightRadiance * cos(\theta) Where cos(\theta) is the angle between the light and the surface normal, and accounts for the light projected onto the surface When considering light reflecting at a point from some...
  47. O

    Monochromatic light and reflection

    http://www.screencast.com/users/trinhn812/folders/Jing/media/07c73e88-45a9-4703-91e1-237b20135d2c I'm not sure why the answer is A. I tried reasoning myself that it has to do with the critical angle, but I can't seem to convince myself.
  48. C

    Light, photons, reflection and percentages

    Hey all, I am new to these forums. I am thinking of taking a distance learning degree in the near future from Open University in Physics, so decided to do some reading up first as it has been a while since I hav etuched physics. Anyway I am reading a book at the minute "Quantam Theory cannot...
  49. D

    Multiple Shock reflection problem

    Here's the problem : Air flows in a passage with an initial Mach No. 2. Determine maximum turning angle A for which 3 regular reflections (i.e. no Mach reflection) of the original oblique shock are possible? Now, what exactly is a mach reflection? Also, what is the minimum Mach number...
  50. A

    What is the cause of reflection?

    what causes the reflection of light from a surface?? why can't light simply move through the shiny surface that reflects it...ya difference in penetrating strength... if we try to explain it at the microscopic level... why would the particles of the shiny surface make it bounce back making an...
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