Questions tagged [reflection]

This tag is for questions relating to reflection, 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. A familiar example of reflection comes from water waves; as the waves travel they reflect off objects that are floating in the water, and also reflect off the walls of the container holding the water.

When a wave reaches the interface between two different media, typically some of the wave will bounce back into the original medium. This process is known as reflection.
A familiar example of reflection is optical reflection in mirrors, where light waves reflect off a smooth surface.
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.
Light reflects from a smooth surface at the same angle as it hits the surface. For a smooth surface, reflected light rays travel in the same direction. This is called specular reflection. For a rough surface, reflected light rays scatter in all directions. This is called diffuse reflection.

1758 questions
22
votes
5 answers

Does a well-lit mirror weigh more than an unlit mirror?

If you weighed a mirror in a room with no light, and then weighed a mirror in a well lit room so that the mirror reflects light, would the weight be different?
Brent
  • 231
5
votes
1 answer

What is the minimum number of metal atoms necessary to make a mirror?

I am still unsatisfied with what I have read so far about the physical basis of metallic mirrors reflectivity. In particular, I am skeptical about the idea that individual electrons serve as mirrors by bouncing back photons, and I am tempted to…
Winston
  • 3,226
5
votes
1 answer

At what direction does a ray reflect at a 90 degrees corner?

Say we pointed a laser that is projected into a $90^{\circ}$corner of a mirror made by perpedicular walls. I know that you cant use tangent since a derivative of boundary of mirror would not exist at a corner. But this didn't convince me that a…
Arbuja
  • 151
  • 6
3
votes
1 answer

Feynman Lectures Vol1-Chap 33-6 : Derivation of Fresnel's Reflection Formula

In Fig. 33–6(a) we see that the field of amplitude b is radiated by the motion of charges inside the glass which are responding to a field a inside the glass, and that therefore b is proportional to a. We might suppose that since our two figures…
3
votes
0 answers

What are the limitations on the Paraxial Approximation?

What my physics book referred to as the paraxial approximation derived to be thus: $$\frac{1}{s}+\frac{1}{s'}=\frac{2}{R}$$ as a way of showing that in a concave spherical mirror, all reflected rays hit the a single point P. I think it is fair use…
2
votes
1 answer

Calculation the reflection coefficient of a mutlilayer material

For our project we have to study an infrared filter. This filter is composed of glass and several layers (nanolayers of titanium oxide, silver and cupper deposited on one side of the glass). Now we have to determine the reflection coefficient of the…
yarnamc
  • 1,201
2
votes
4 answers

Why does light seem to reflect preferentially off surfaces and interfaces even when the stuff in question is non-opaque?

Glass is said to reflect about 4% of incident light. The other 96% is either absorbed or transmitted. That 4% seems to reflect from the surface of the glass. From the perspective of a 'stream of photons', what's special about the surface as opposed…
Andrew
  • 155
2
votes
2 answers

Crushed pebbles shone differently when viewed from different angles

I was roaming in a field. Crushed and pulverized pebbles were scattered in a corner of the field. From where I stood, I could see that some of the pebbles shone extraordinarily in the sunlight, while others remained ordinarily lit. I changed my…
2
votes
1 answer

Magnifying glass as a mirror?

I understand how a magnifying glass works as a convex lens, however I am curious as to how one can explain using it as a mirror. When I observe the reflections off of a magnifying glass, strangely enough it seems to create two reflections: one that…
2
votes
1 answer

What are the properties of center of curvature of a parabolic mirror?

What is so special about the center of curvature of a parabola (since a parabola can't actually have a center) ? I mean, it must be something unique for it to be defined. Why is it twice the focal length? What are the geometrical properties of the…
Gauri
  • 291
2
votes
1 answer

What's the need of a polished surface in a plane mirror?

In a plane mirror, my textbook tells me that in a plane mirror one surface is polished and the other is silvered. If light gets reflected from the silvered surface, why does the polished surface have to be there?
2
votes
1 answer

Converging mirrors and the transition between inverted and non-inverted images

I was talking with a friend recently about concave mirrors, which frequently invert the reflected image - I think we were playing with a spoon. I raised the question, if you had a mirror whose shape could be easily controlled so you could move it…
Mr. Boy
  • 1,006
2
votes
2 answers

Aluminum foil to reflect sunlight from behind a textured glass

I'd like to keep room(facing east) cool during mornings. The room covered with textured glass on the east. By how much can I reduce heating by sticking the aluminum foil on the inside behind the glass. I understand that the glass/foil will be heated…
1
vote
2 answers

Doubt regarding the mathematics in reflecting surfaces

So the question goes as follows "A reflecting surface is represented by the equation x² + y² =a². A ray travelling in negative x-direction is directed towards positive y-direction after reflection from the surface at point P. Then co-ordinates of…
Ham Lemon
  • 203
1
vote
0 answers

Any cool Total Internal Reflection phenomenon ideas for a project?

I'm doing a project about any TIR phenomenon and was wondering if anyone has a cool idea of what to do. I talked with my teacher about mirages, but she wanted something that was a little more unique. However, I am currently having trouble finding…
1
2 3