Reflection Definition and 915 Threads

Hello, i have a very basic question about reflection of infrared light. What types of materials will give a diffuse reflection of light in the near IR spectrum (around 850nm)? Is the original wavelength affected by this reflection? thx in advance, michael .

If there is a "red" color ball people told me that if i shine white light on it the "red" color ball absorbs all the light and reflects "red" photons hence we perceive it as "red" colored Is this true? if this is right i want to know more details... what does reflect mean here? what does...

Hi, I'm currently looking into reflectivity and emissivity of metals in sunlight. However, I can't quite grasp how the mechanisms of reflection and emission differ. Emission obviously occurs because an electron is exited by a photon and then is de-excited and emits photon or photons. However...

Homework Statement A point source of light is at depth h below the surface of a large and deep lake. Show that the fraction, f, of the light energy that escapes directly form the water surface is independent of h and is given by f=0.5(1-\sqrt{1-1/n^2}) where n is the index of...

I have a question which may be based in a complete misunderstanding of how "color" and our perception of it works in terms of objects absorbing certain wavelengths of light and reflecting a certain length to show that color. My question is why does an object reflect a specific wavelength...

Hello fellow physicists :) I have recently done an experiment and am trying to propagate the uncertainty. Unfortuantely, I haven't done that in years, and need to remember how its done. For example: When theta= 20 (+-2) I want to find sin20 and the uncertainty: sin20=0.34 (+-?) How can I...

Homework Statement Let \sigma^+ light [left circular] be incident on a piece of glass, with incidence angle = 45^\circ. Characterize the polarization of the reflected light. The attempt at a solution My first thought is to simply treat the components of the electric field (Ex,Ey) as...

What is the difference between them. Even in total internal reflection not everything is reflected. I don't get it what is the big deal?

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...

Hi, I am trying to calculate the power of a reflected electromagnetic field and can't find a physical explanation for a given solution. I've noticed the following example: The Plane has a radar for altitude measurement which emmits the power Ptx at the frequency ftx. Calculate the power...

Homework Statement An electromagnetic wave is incident upon a planar interface at an oblique angle \theta_i, where it is reflected. For the wave vector components parallel to the interface, we have k_{xi}=k_{xr}. Thus, \theta_i=\theta_r. The wave numbers for the incident and reflected waves...

Hello every body; I am having a problem understanding how light is polarized by reflection, what happens during the process, and why is it polarized at a particular angle "Angle of Polarization". Can you please help me with this problem? I'll be thankful.

two plane mirrors facing each other are 10m apart. A woman stands 3 m from one of the mirrors and looks at the mirror and sees two distinct images. How far are these images from the woman? this one is a bit confusing.. can somebody knows how to solve it?

Snorkeling in the Red Sea, I noticed fish that were near the edge of my purple-range. They were small--perhaps 3-5 inches. Looking at guides I would say they were angelfish or anthias, but surely there are marine biologists who know exactly what these were. I have see other purple fish, these...

This is a picture of me in my bath. (dont worry, it is purely diagramatic!). I face a wall to the front of the bath. There is also a wall to the left hand side of me. Both with shiny tiles. Their is a light above me and slightly behind to my right. While relaxing, I took note of the light bulb...

Homework Statement What is the minimum thickness of coating which should be placed on a lens in order to minimize reflection of 661 nm light? The index of refraction of the coating material is 1.40 and the index of the glass is 1.65. Hint: You must take into account the 180 degree...

Hello everyone, I am new here to the physics forums. So for my first post I need some help on this problem from my homework. Here we go: A laser beam of wavelength 632.8 nm shines at normal incidence upon the reflective side of a compact disc. The tracks of tiny pits in which information...

Problem statement. A spherical wave (from a point source) reflects from a planar surface. Draw a ray diagram and sketch some wavefronts for the reflected wave. Attempt It is easy to sketch some wavefronts for the reflected waves; however, how is it possible to draw a ray diagram for...

Excuse me if this question is obvious. Do mechanical waves propagate through loudspeaker diaphragms (whether they be elastic or rigid) in the same way that acoustic waves propagate through waveguides albeit a different medium? As far as I understand, reflections occur at the boundaries of the...

Hi, Can someone please eloborate me why the Angle of Reflection is always same as the Angle of Incidence. I want the explanation at photon and molecular interaction level. Thanks in advance. - Pavan.

Hi! The diagram below shows two mirrors X and Y, and a solid object with white spots at P and Q. http://img199.imageshack.us/img199/9284/unbenanntcwz.jpg An observer at A sees an image of P reflected in mirror Y. Mark R, the position of this image, and draw a ray from P to the...

Hi all! I have a problem about the phase shift an e.m. wave acquire when, traveling through air, it's reflected back by a mirror (or a beam splitter) with n > n(air). Now, I know the example of the thin film interference due to a π shift of the wave reflected by the medium. But I see...

Homework Statement To find the total internal reflection. This equation should give me 1.48 as the answer but it doesn't. Can you please give me other ways to figure this out. I really need this. Homework Equations n1sin1Ө=n2sin2Ө n1 = 1 n2 =? sin1Ө = 44 degrees sin2Ө = 48 degrees...

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...

1. A light source, S, is located 2.0 m below the surface of a swimming pool and 1.5 m from one edged of the pool. The pool is filled to the top with water. a) At what angle does the light reaching the edge of the pool leave the water? b) Does this cause the light viewed from this angle to...

I have tried searching for answers to these questions but i can't seem to find them, so if anyone could help me it would be greatly appreciated. How efficiently you can reflect microwaves? I know visible light can be reflected at 99.99% efficiency or something ridiculous like that, is it the...

Hi. I've been trying to understand the phenomenon of step potential, when energy of particle E is higher than the potential V. Then we have solution on both sides of boundary in the form of wave functions... Is the reflection coefficient in this case simply (E-V)/E ?? Can anyone show me a...

Is it possible to reflect an electron wave at an angle while maintaining coherency throughout the process? I found this but I don't think it talks about coherently reflecting *at an angle*: http://eprints.ecs.soton.ac.uk/16241/1/paper_16.pdf Thank you!

Homework Statement What are the difference among angle of incidence, reflection, and refraction when light strikes two parallel surfaces? What does it mean "light is incident on film"?-is that the angle of incidence? The Attempt at a Solution I know how to find all of...

Can someone explain to me why do we use this for boundary conditions in the heat, and wave equations? Why must we make an odd extension of our initial data and not even?

Hi all, The relation between the magnitudes of the incident, reflected and transmitted waves are obtained using Fresnel coefficients. If a field moves from air to a more denser medium, which field should have a greater magnitude (reflected or transmitted)? I thought that it would be the...

Hi all, I was reading "Geometrical Optics Reflected Fields" chapter from "Introduction to Uniform Geometrical Theory of Diffraction" textbook. The author assumed that the surface is perfectly conducting and therefore he only considered the reflected waves. He derived a formula for the...

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...

Homework Statement Given the matrix A= -1/2 root(3)/2 root(3)/2 1/2 determine if the matrix is a rotation about the origin or a reflection about the positive x axis and find the angle between the that the line makes with the x-axis Homework Equations The...

Homework Statement A river canyon is 147 m across as shown in Figure P.32. You are located on the river surface and clap your hands once to generate a brief acoustic pulse. You detect a time interval of 0.407 s between the twin echoes recorded on tape, analyzed when back home (?) in a...

Homework Statement The prism is replaced by a new prism of the same shape, which is set in the same position. The light beam experiences total internal reflection at the right surface of this prism. What is the minimum possible index of refraction of this prism? Homework Equations...

1. What is the change in momentum of a photon when it bounces off a mirror? (assuming it's a perfect mirror) My guess is that it's 2h/\lambda. But i think it should be more complex than this.

Hi, I learned optics with pedrotti optics book. It is suppopsed that light is reflected on surface of first layer and then tranmited wave is also reflected on surface of second layer, So there is Double Layer incident light get there. According to book, If two reflections are...

Homework Statement A transparent film (n = 1.5) is deposited on a glass lens (n = 1.65) to form a nonreflective coating. What is the minimum thickness that would minimize reflection of light with wavelength 500 nm in air? Homework Equations 2nt = mλ n = refractive index of film t =...

Homework Statement To find a transformation that reflects a vector in a line that does not pass through the origin. The Attempt at a Solution I've been trying to work this out for a little while and I found that I can do it if I use the vector for the 2d transformation with a 3x3...

Homework Statement Light is incident normally on the short face of a 30-60-90 (degree) prism. A drop of liquid is placed on the hypotenuse of the prism.If the index of the prism is 1.68, find the maximum index that the liquid may have if the light is to be totally reflected. Homework Equations...

Bragg "diffraction" or "reflection" As you read about X-ray (or neutron) diffraction in solids, you come across authors who use the term "Bragg diffraction" and others that use the term "Bragg reflection". Some authors even use both terms in the same edition of the book (Kittel, 5th Ed.,, I...

Why does total internal reflection happen in glass?

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...

Hi all ,it is my first post so sorry if I make any mistake ,we all know about the total internal reflection in which when we passed light in any material with an angle greater than the critical angle then it will bound or catch inside the light, Now I want to prepare a list of the such...

Homework Statement A mirror moves perpendicular to its plane with speed (beta)c. A light ray is incident on the mirror from the \forward" direction (i.e., vm dot vl < 0, where vm is the mirror's 3-velocity and vl is the light ray's 3-velocity) with incident angle µ (measured with respect to...

1. A ray of light is incident onto the interface between material 1 and material 2. There is a figure, which is a standard figure of a ray in medium of n1 striking an interface where medium2 (with n2) meets medium1. As is typical, some of the light is reflected and some is refracted. The...

At what angle of incidence is amplitude coefficient of reflection parallel to the incidence plane 0? my solution is that by Fresnell's equation, r//=tan(i-i`)/tan(i+i`)=0, i=i`,i=90.so for whatever surface,angle of incidence should be 90. is it correct? different from the answer!

I seem to recall it is possible to change a wave's frequency, pattern, and amplitude by adding another wave to it. Is it possible to add a second wave to a Sine wave to turn it into a cosine wave of the same amplitude and how would you do this? I'm thinking if I had an amplitude 1 for the...

Homework Statement 1. The index of refraction for water is 1.33 and that of glass is 1.50. a. What is the critical angle for a glass-water interface?b. In which medium is the light ray incident for total internal reflection?Homework Equations nisin\varthetai=nrsin\varthetarThe Attempt at a...