What is Light reflection: Definition and 39 Discussions

Light or visible light is electromagnetic radiation within the portion of the electromagnetic spectrum that is perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths). This wavelength means a frequency range of roughly 430–750 terahertz (THz).

The primary properties of visible light are intensity, propagation-direction, frequency or wavelength spectrum and polarization. Its speed in a vacuum, 299 792 458 metres a second (m/s), is one of the fundamental constants of nature, as with all types of electromagnetic radiation (EMR), light is found in experimental conditions to always move at this speed in a vacuum.In physics, the term 'light' sometimes refers to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays, X-rays, microwaves and radio waves are also light. Like all types of electromagnetic radiation, visible light propagates as waves. However, the energy imparted by the waves is absorbed at single locations the way particles are absorbed. The absorbed energy of the electromagnetic waves is called a photon and represents the quanta of light. When a wave of light is transformed and absorbed as a photon, the energy of the wave instantly collapses to a single location and this location is where the photon "arrives". This is what is called the wave function collapse. This dual wave-like and particle-like nature of light is known as the wave–particle duality. The study of light, known as optics, is an important research area in modern physics.
The main source of light on Earth is the Sun. Historically, another important source of light for humans has been fire, from ancient campfires to modern kerosene lamps. With the development of electric lights and power systems, electric lighting has effectively replaced firelight.

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  1. B

    How does reflective photoelasticity work on transparent glass?

    https://glassphotonics.com/all-products/grey-field-polariscopes/gfp2600-product-line/ In this link you can see a photoelasticity instrument that is all-in-one, and compact. Traditional photoelasticity (left hand side, (a), in this picture) is not compact and has an awkward apparatus setup where...
  2. O

    B Parallel light reflection for a one-way speed of light measurement setup

    Hello, Is there a mirror that will reflect light in parallel trajectories ? If yes, is the reflected light in sync, and will all beams hit a flat surface simultaneously ? Thank you
  3. J

    Light Reflection and Particle Size

    I'm studying particle counters and one of the detection methods uses reflected light to determine the sizes of the particles. What principle does it base on? Thanks!
  4. Neeraj

    Light Reflection Momentum - P=2Icos^2(A)/C

    Even if a beam of light strikes a reflective surface at an angle 'A', the change in momentum should be 2mc, P=2IcosA/C but I find it P= 2Icos^2(A)/C.
  5. F

    What is the equation for constructive interference in thin film interference?

    Homework Statement Between two pieces of glass (##n_1=1.70##), there is a thin film of water (##n_2=1.33## and width ##d=1 \mu m##). If there is normal-incidence of white light on the water surface, find: (a) which wavelenghts can be seen in the light transmitted (answer: 667 nm,533 nm,444 nm...
  6. S

    Reflection of only visible (safe) light on moon/mars

    I have seen many articles lately regarding planned manned missions to the moon and Mars but the question of radiation protection constantly comes up. Engineers keep proposing various shelter designs that use local materials (regolith) as a concrete base to absorb harmful radiation so that the...
  7. Georges

    Light Reflection: A 3D Designer's Guide

    Light is Reflected from the surface of the object or pass through it(interior) and then the light is reflected ? Sorry for my "noob" question i am a 3D designer just looking for some more knowledge Thanks in advance
  8. Latempe

    For the Fresnel Equations for TM light why is 1 + r not t?

    The complex amplitude ratios for light are defined as: rTM = ErTM / EiTM tTM = EtTM / EtTM I've done the derivation from Wikipedia and see that (n2/n1) * tTM = rTM + 1. But I don't understand what is going on physically. I understand that these values are not power or intensity so I can't...
  9. C

    I Visible light reflection v.s X-Ray reflection

    I'm a bit new to studying physics so I hope this question doesn't sound off. I already know this "Photons are emitted from an atom when an electron transitions from one state to a lower-energy state. The energy of the emitted photon equal to the difference in energy between the two states."...
  10. DavidReishi

    Is there a limit to the amount of info in reflected light?

    Sunlight hits our planet, for example, and reflects light outward back into space. Hence why photos can be taken of Earth from outer-space. But if we disregard technological limits to optics, etc., then in theory how much information does this reflected light contain? Is it rich enough, for...
  11. Ookke

    Light reflection in length contracted system

    Light beam hits the mirror perpendicularly and returns to the source (left picture). The same system in horizontal motion (right picture) is skewed due to length contraction so that both beam and mirror are at higher angle. Because the beam returns to source in the system's rest frame, it must...
  12. D

    Theoretical 100% Light Reflection Room

    If there was a room with all walls that are 100% reflective and a light source. If you were to instantaneously remove that light source, would the room still be lighted? If yes, if an object and the light source were previously present the room, and were to be instantaneously removed, would the...
  13. 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...
  14. 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?
  15. 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...
  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. 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...
  18. M

    Light Reflection: Path Length Difference?

    Homework Statement When light reflects from a thin film back toward the source, what is the path length difference? The Attempt at a Solution A. It is equal to twice the thickness of the film. B. It is equal to the thickness of the film. C. It is equal to half the thickness of the...
  19. S

    Light Reflection Question: Velocity and the Infinite Mirror

    Consider i m moving at a velocity considerable to the speed of light. Above me there is a mirror stretching to infinity . It doesn't move with me. Now if i shine light on the mirror where will the reflected beam hit me?right on me, back of me or infront of me?
  20. 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...
  21. 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.
  22. 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...
  23. S

    What is the relationship between the reflection angles in a prism?

    Homework Statement For a beam of light shone on a prism, the reflected beams will give twice the angle of the prism. Homework Equations We know that the angle between the incident ray and the normal = angle between reflected ray and normal The Attempt at a Solution i tried drawing...
  24. M

    Polarized Light Reflection: Solving for Intensity

    [b]1. A person riding in a boat observes that the sunlight reflected by the water is polarized parallel to the surface of the water. The person is wearing polarized sunglasses with the polarization axis vertical. If the wearer leans at an angle of 17.0 degrees to the vertical, what fraction...
  25. N

    What Software Can Simulate Light Reflection for a Solar Heliostat Project?

    Does anyone Know a program that can simulate light reflection in a 3d environment, to help me in my project "Solar Heliostat". I want the program to determine the angle of reflection and the size of the beam of light on the desired target.
  26. C

    Light Reflection: Can Sunlight Take Craft Back to Launch?

    You know when people say they have a craft out in space and use the sun light to move it by bouncing it off mirrors . so I take it you would never be able to get the craft back to where you launched it using light from the sun. Or would this work to get it back rotate the mirrors with an...
  27. T

    Light Reflection Mystery at the Rijksmuseum Amsterdam

    I took this photo in the Rijksmuseum Amsterdam. I hope it can be seen but the reflection of this silver thing is different colours in the different panes of glass. (Blue behind it, orange/red to the sides). What causes this effect? And why the particular colours...
  28. L

    Does the reflection of light on water affect the color of objects?

    Hello, I'm not sure if this is the right place as it's not quite a technical question, but I hope you guys can help me. I have a question about a certain situation involving reflection of light and how it effects color, and it requires somewhat of an 'artistic' eye. I had a little debate...
  29. B

    Light reflection by traffic light after rain

    Hi. I need to write up a short one paragraph on a picture I took-- I just need hints or suggestions so I can go and research the effect myself. Any insights would be greatly appreciated. I have a picture of a traffic light (red). The ground is wet after rain. The red light is smeared out...
  30. R

    Optics, lenses, and light reflection

    Hi, I'm new to this place, and I'm not sure if my problem fits with this forum, but I'll give it a try. Right now, I'm building a laser range finder, but my biggest concern will be focusing the reflected laser beam onto a small silicon photodiode. And to add to that, I have barely any...
  31. F

    Light Reflection between Mirrors: Facts & Myths

    Why are we not able to capture and store light between two mirrors? I'm going to take a guess at the answer but I'd like to hear from someone who knows for sure... I'm wondering if you actually can for a small amount of time, but the inefficiencies of an imperfect mirror cause some light to be...
  32. K

    Question about light reflection

    Homework Statement A diver shines a flashlight upward from beneath the water at a 23.0° angle to the vertical. At what angle does the light leave the water? Homework Equations I thought that i could use snell's law here...but i don't know what to do afterwards... The Attempt at a...
  33. M

    Problem 23.11 Light reflection

    Homework Statement It is 171 cm from your eyes to your toes. You're standing 210 cm in front of a tall mirror. How far is it from your eyes to the image of your toes? Homework Equations ? The Attempt at a Solution The answer which I got from the back of the book is 433cm. I have the...
  34. T

    Visible Light Reflection from Oil-Water Interface in Parking Lot

    A tiny layer of oil (n = 1.25) is situated on top of a water puddle (n = 1.33) in a parking lot. If the thickness of the oil is 242 nm, the what color(s) of visible light will give a strong reflection? 2t=m*lambda/n2 2t=242nm/1.25 and then 2t=242nm/1.33 i just don't know what goes where...
  35. I

    Light Reflection Through Mirrors

    What are the ways that things can be reflected through flat, converging, and diverging mirrors? I know that for flat mirrors it's a virtual image equal to the size of the object For the converging mirror, if the object is placed farther than the radius of the mirror, the image is real and...
  36. K

    Light Reflection at a Point: Exploring Possible Answers

    imagine that i have a pair of LEDs throwing light on the same point on a piece of paper. This is possible if the LEDs are inclined equally at an angle to the normal coming out of paper, right? now if i consider two rays hitting the paper at the same point, then where can i explain the...
  37. E

    Need help with light reflection problems

    Need urgent help with light reflection problems Here are my problems: 1) A beam of light has a wavelength of 610 nm in vacuum. a: What is the speed of this light in a liquid whose index of refraction at this wavelength is 1.45? I used n=c/v to get 2.07x10^8 m/s. This is correct. b: What is...
  38. M

    Investigating a Light Reflection Experiment

    I'm doing an response on a little experiment done in class. I'm having trouble understanding some parts. If someone could reply to the information below, it would really be appreciated. A large beaker is filled with water, it is covered on the outside by construction paper (any coulour you...
  39. T

    Understanding Light Reflection and Black Bodies in Nature

    One thing that has allways disturbed my mind is the correct understanding of lightinteractions in nature. When we're talking about light reflection (light that is reflected in an arbitrary direction, not like mirrors) is it really reflections or is it new light created by the incoming light...