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.
I'm surprised to have reached this far in a forum. My earlier record was 200 in a Diablo 3 gaming forum, and I have a strong passion for that game.
I guess knowledge is a virtue that I just can't let go, so this is why I'm still here today after about one and a half years. I have really...
Homework Statement
find the matrices representing linear map T:R3 -> R3 with respect to the standard basis
Homework Equations
T reflects each point in the (x,z)-plane
The Attempt at a Solution
I can't figure out how does x,z plane looks like...
A small source of light at the bottom face of a rectangular glass slab 2.25 cm thick is viewed from above. Rays of light totally internally reflected at the top of the surface outline a circle of 7.6cm in diameter in the bottom surface. Determine the refraction index of the glass.
This is...
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...
Hi guys, i need some help on this topic.
Basically, i need to calculate the angle of reflection of a oblique shock on a solid boundary.
Here is the description of the question i have:
an incident supersonic flow reaches a compression corner, with a deflection angle of 15 degrees...
Could someone explain to me what ionospheric heaters (like the one at EISCAT) do...in lay-mans terms?
And what exactly is ionospheric reflection...again, in lay-mans terms.
Thanks.
I was just reading my book when it said that the fact that Newtons rings were always dark in the center where the lens touches the glass plate is proof that reflections are 180 degrees out of phase with the incident light, but after further thinking, I think that logic doesn't make complete...
Homework Statement
The drawing shows a crystalline quartz slab with a rectangular cross-section. A ray
of light strikes the slab at an incident angle of 1=34o, enters the quartz and travels to
point Po (Figure2). This slab is surrounded by a fluid with a refractive index n...
I'm wanting to get another optics book. I'm interested in finding a book that gives insight into how light waves interact with surfaces such as in reflection and x-ray diffraction and things like that using sufficient diagrams of the wavefronts and particles and rayleigh scattering. I want to...
Homework Statement
Consider a common mirage formed by superheated air just above a roadway. A truck driver whose eyes are 2.00 m above the road, where n=1.0003 looks forward. She has the illusion of seeing a patch of water ahead on the road, where her line of sight makes an angle of 1.20...
I've two questions here:-
1) Sound reflects it is said using laws of reflection of light.So,it means we hear max. sound when angle of incidence is equal to angle of reflection,right?& if not equal then what do we hear or not?
I guess we hear lesser than max.sound when the angles are not equal...
Think of this one (you can test it) - it's a foggy night and you are approaching a sreet light under which is a puddle of water. Beacuse of the fog you see a diffuse image when looking directly at the light, however, when looking at the reflection, yoe see a clear, sharp image. Why? Can anyone...
Homework Statement
What is the thinnest film of a coating with n = 1.43 on glass (n=1.52) for which destructive interference of the red component (660 nm) of an incident white light beam in air can take place by reflection?
Homework Equations
2t = m*lambda?
The Attempt at a...
Homework Statement
A glass lens is coated on one side with a thin film of magnesium floride (MgF2) to reduce reflection from the lens surface. The index of refraction of MgF2 is 1.38; that of the glass is 1.50. Assume that the light is perpendicular to the lens surface and that the thickness...
Hi everyone
A few weeks ago, I had worked out the relations between the angle of reflection and angle of incidence in case of reflection from a plane mirror,
(1) moving toward the incident ray
(2) moving normal to the incident ray
(PS -- This is not homework.)
The way I did it was...
Hi,
I'm working through an Excercise in Sean Carrol's spacetime and geometry book. The question asks you to consider an inertial frame S with coordinates x^\mu=(t,x,y,z) and a frame S' with primed coordinates. Which is related to S by a boost v in the y direction. Imagine a wall( or mirror)...
Hello forum , i have a spindle motor from an HDD and i pasted to this motor 6 facets polygonal mirror, the problem is that the mirrors are not 100% alignment ( it's hand made) and the laser reflected from this mirrors is doing 6 lines ( where it should be one line if all mirrors are good...
Optics -- How long can I see an objects reflection
Homework Statement
The object is traveling at a constant velocity of 4 m/s. Initially, the observer can not see the object. At a certain point, the observer can see the reflection of the object in the mirror. For how many seconds is the...
Homework Statement
Three objects P, Q, and R, are viewed through a plane mirror AB. When an obstacle is moved towards the mirror, which object "disappears" (i) first; (ii) last?
Diagram. I will describe it in words. The mirror is horizontally placed. Q is placed 10 cm directly above edge...
I feel a bit dumb, but could someone help me see this:
G(s):= \int_{-\infty}^{\infty}f(-x)e^{-2\pi isx}dx = \int_{-\infty}^{\infty}f(u)e^{-2\pi i(-s)u}du = F(-s)
Homework Statement
A particle of energy E approaches a step barrier of height U0. What should be the ratio E/U0 so that the reflection coefficient is 0.43?
Homework Equations
R=(k1-k2)^2/(k1+k2)^2 <--------reflection coefficient
The Attempt at a Solution
I am completely stumped...
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...
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.
"Half-silvered mirrors" and transmission and reflection
I am curious about any equations (whether empirical or no) that can predict the thickness of metal (on a glass substrate) needed for a given transmission/reflection ratio. Gold, aluminum or silver, it doesn't truly matter. This should...
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...
Hi
Not sure of optical questions should go here to general physics questions, but here goes.
I have a doubt, basically, what consists of a reflection?
If i have a perfectly smooth surface, then the specular highlights are infinitely thin, and you should have perfectly mirror-like...
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...