will da focal length of a concave mirror change if placed in water?
148730
I think it will not change. The reflected ray has to have the same angle. The ray passes through water and refelcts in the water. \nWhat changes is the direction of the ray coming from the air, and then going through the water, but this will not change the focal lenght. Focal lenght is just a matter of geometry of the mirror.
1179980
Just as with any other kind of lens, the shape of the lens will be one of the parameters that affects the focal length, but I’ll assume you will use the same-shaped container to look at the differences between different liquids.  (The material that the container is made of will also affect the focal length, but I’ll also assume that’s constant, too.)\n\nIn this case, there are really only three things that matter, and if you use a single color light source (e.g., a red laser pointer), only the first matters.  Even if you don’t, the second parameters listed below are normally of much less importance than the first.\n\n1.The refractive index of the liquid\n2.The chromatic dispersion of the liquid\n3.The wavelength (color) of the light being sent through the lens.\n\nThe primary parameter is the refractive index; which quantifies the extent to which a light ray is refracted (“bent”) as it crosses the interface with the liquid and whatever is on the other side of the liquid (i.e. the container material).  For a given shaped lens, a higher refractive index liquid will cause more refraction, and hence result in a “stronger” lens.\n\nThe chromatic dispersion tells you how much the refractive index varies as a function of the wavelength of the light.  All real materials have some dispersion, and because the refractive index for different colors of light are slightly different, the focal length and focal point of any real lens is slightly different for different colors.  (Manufacturers of things like high-quality camera lenses take great pains to minimize the dispersion of their lenses by using multiple optical elements (individual lenses) made of different materials.)\n\nFinally, because the index of refraction varies as a function of wavelength, the focal length will also depend on the wavelength of the light you use.\n\nIf we ignore the last two effects (e.g., let’s say you use a laser pointer as the light source, we can concentrate on how you might vary the refractive index of liquid you use.  First, different liquids have different refractive indices because they have different chemical compositions and molecular makeups.  Materials have characteristic refractive indices because of the way light interacts with the atoms and molecules making up the liquids.  Different molecules interact with light in different ways, giving rise to differences in refractive index.  \n\nYour first experiment might then look at different composition liquids (oil, water, alcohol, water containing the same concentration of different dissolved substances, water containing different concentrations of the same substance, etc.).\n\nSecond, to a much lesser extent, the refractive index of a material depends on temperature (mostly because the density of materials depends on temperature).  You could try looking at the effect of heating the same fluid to different temperatures and seeing if that makes a measurable difference in the focal length.  Different fluids will have different temperature dependences.
36159
As mechanical engineer this is out of my normal field but felt you deserved an answer of some sort.\n\n"Because of diffraction effects caused by slits or apertures in optical measurement systems, the radiation energy which is directed towards a particular region on a sample will be spread over a larger area than desirable. By employing an apodizing filter in the radiation path in such system, diffraction tails of the system will be reduced. The apodizing filter preferably has a pattern of alternating high transmittance areas and substantially opaque areas where the locally averaged transmittance function is an apodizing function. In the preferred embodiment, the locally averaged transmittance function varies smoothly and monotonically from the periphery to the center of the filter"\n\nI see the theory here, also found on on using an apodizing mirror to stabalise images in a telescope\n\n"I built and used an apodizing screen for my 6" f/8 scope many years \nago. I made it by layering several layers of window screen, each one \nwith a circular cutout of different diameter. The result was an aperture \nmask with a step-wise approximation to a smooth apodizing function. It \nwas claimed to improve contrast for planetary viewing. Anyway, my \nexperience was that it seemed to make the image more stable but if it \nimproved contrast, I couldn't see it. If you do this on-axis, the \ndownside is that your diagonal mirror will now become more of a factor \nin the contrast equation. The bottom line is I wouldn't recommend it."\n\nAlso "An excellent reference for all sorts of technical techniques is\n>"Procedures in Experimental Physics" (also printed under the title\n>"Physical Laboratory Practice") by John Strong.  I don't recall the\n>publisher, but it came out in the 30's.  The bad news it that it's been\n>out of print for decades (and some SOB stole the copy I got from my\n>father!); the good news is that an outfit called Lindsay is reprinting it\n>in paperback.  (Don't have their name/address here in the office; I'll try\n>to remember to look it up tonight.)\n>\n>                            Dr. Kurt Hillig\n\nEvery ATM should have a copy of this great book. Lots of stuff on\nmirror making, figuring, special laps,making flats, prism ,etc.\nThere is nice modifed Draper machine ( upper disk also powered)\nand a homemade diamond cutting wheel to cut small glass blocks.\n( I would like to build this one someday ) A great section on\nkinematical mechanical construction. Yeah this a mid 30,s book but the \ninfo\nstill can be used. No I don't work for Lindsay Publications,<G>\n\nBob Pfaff\n\n\n This book, in paperback form, can be ordered from\n      http://www.amazon.com, on the Web. It can also be ordered\n      through your local bookstore. Amazon prices it at $23.95, and\n      provides the following information:\n\n      Published by Lindsey Publications\n      Publication date: June 1986\n      ISBN: 0917914562"\n\nSorry couldn't find any really decent expplanations, but at least you've got a starting point.
803236
LGP depends on the area of the objective lens/mirror.  Area depends on the square of the diameter.  So take the ratio of their diameters (express them both in the same units first!) and square that ratio - that will be your answer.
220714
it works by principle of multiple reflection. This is achieved by keeping mirros in an angle that the light from the base plate gets reflected by many mirrors before travelling your eyes via the cylinder. This is almost the extension of concept where people keep huge mirrors in shop to provide an illusion that it is a big shop.
1022562
A Fresnel lens works just the same as a standard convex lens (or any positive lens).  The only difference is that a Fresnel lens is flat!\n\nThe magnification is related to the focal length of the lens.\n\nHere is a good explanation for calculating the magnification...\nhttp://en.wikipedia.org/wiki/Magnification
1151441
#1: It doesn't. The frequency of a beam of light remains constant regardless of the medium through which it travels, although the wavelength may change.\n#2: Absolutely nothing, for the same reason as #1.\n#3: Not for a mirror. The focal length of a mirror is determined by reflection, not refraction, and the angle of reflection is equal to the angle of incidence, regardless of the medium.\n#4: 1:1. The velocity of light does not depend on wavelength*\n\n*okay, for some materials the index of refraction, and therefore the speed of light in that material, depends slightly on wavelength, which is why a prism can be used to separate light into its various colors. However, the question did not specify a particular medium, so I assumed it meant in vacuum, where the velocities of all light rays are indeed the same.
1151404
If the deflection surface has any diffraction or diffusion to it, the light may just be redirected imperfectly. 12kV? Jumpin Gigawatts!
524755
You are measuring the distances from the mirror.\n\nThe focus is behind the mirror. Therefore take that as - 53cm.\n\nThe object is at + 25cm.\n\nWe have to find v.\n\n1/f = 1/u + 1/v. \n\n-1/53 = 1/25 + + 1/v..\n\n+ 1/v = -1/53 - 1/25 = - 17 cm.\n\n17cm to the back of the mirror.\n\nA convex mirror focus distant objects at the focus.  If the object is brought nearer and nearer, the image moves from the focus toward the mirror.\n In your problem the object is very near to the mirror.  The image must be nearer to the mirror. \n Your answer -47 cm implies it is very near to the focus (-53cm) and it cannot be the correct answer.
658850
you can try total internal reflection of light using a keychain laser (commonly availble) and tub filled with water. all you have to do is put a small piece of mirror in the tub filled with water, let laser fall upon it. see the trajectory of the reflected beam ofr different orintations/angle of reflections and you will find that for certain critical angle the reflected beam is trapped in the water due to the internal reflection of the laser. you can do the same thing by choosing a transparent bottle with a small hole on the curved surface close to the base. now fill it with water, and see that water flows out of the hole in a parabolic fashion, now shine the laser from the opposite side to illuminate the water column. take a white plastic sheet allow the water to fall upon it, you will find that the water emmits light. this also explains how fibre optics work.
895487
b- It has a concave primary mirror and flat, diagonal secondary mirror.
968157
I would also pick A as the correct answer.\n\nB. the camera might or might not have to be adjusted depending on how much light is being reflected into the picture.\n\nC. A reflector may or may not prevent one side othe image from appearing lighter or darker depending on the actual lighting of the scene.\n\nD. because B & C are not right
94535
Chromatic aberration is color smearing.  It is much more likely to occur in a lens than a mirror, since the amount of refraction in the lens depends on color, which is how a prism rainbow works.\n\nSpherical aberration is blurring caused by the mirror having a spherical shape.  A parabolic mirror won't have this.
52768
B.  A convex mirror will make light diverge, and no mirror will *alwats* give a inverted image, because it depends whether you're closer than the focal point for a concave lens.\n\nThink about those little round mirrors on buses and huge trucks, and how small the image is.  Those mirrors are convex.
792242
They are almost the same size, you are right  - the reflective image is smaller. The reason it looks bigger is because you are looking at a more or less 2-dimensional image. You have to physically look from the top to the bottom. I don't know if this is a good example, but think of a hockey goalie protecting his goal. The further out he moves, the more of the goal he covers. He looks like a giant to the shooter because he has to move his head to see from his head to his feet. \nHere's one for you - how large vertically does a mirror have to be in order to see your total reflection? It doesn't matter how far away it is?
593131
The incident ray is perpendicular to the surface of reflection.\nThen one has the least distance case.
774526
On a smooth surface, the angle of reflection will be the same as the angle of incidence.\n\nTherefore, the answer is (B) 40 degrees.