Lens Definition and 787 Threads

1)Is it possible to concentrate infrared radiation from a blackbody with a lens? 2)Should a lens be at different temperature from a blackbody?

Homework Statement A convex lens forms an image 8.96 mm on a screen. Keeping the screenand the object fixed, the lens is moved through a distance of 15.4 cm and a sharp image of the object is again observed on the screen. If the length of the second image is 3.54 cm, calculate the focal length...

A certain 0.86 cm lens is used in a peephole for hotel room doors for safety reasons. The tenant sees the maid in the peephole but she is reduced in size by a factor 0.01. A. What type of lens must be used? B. Where is the image of the maid located? C. What is the power of this lens...

Homework Statement A 1.5 cm high diamond ring is placed 20 cm in front of a convex lens whose radius of curvature is 30 cm. a) What is the position and the size of the image? b) What magnification does this lens have? Homework Equations 1/f= 1/di + 1/do m= -di/do or hi/ho The Attempt at a...

Homework Statement An object is locted 15cm infront of a convae lends with a focal length of 10cm. use ray tracing to determine the location of the image. try to draw to scale i)is the image upright or inverted? ii)is the image real or virtual? iii)use your ray-tracing diagram to...

Hi, I need someone to outline how to get the solution of the problem which is: An object 8.0 cm high is placed 80 cm in front of a converging lens of focal length 25 cm. Calculate the image position and height. Thanks, Eric

Homework Statement Following data recorded: Di (distance image to lens) 6.0 8.0 10.0 12.0 14.0 Magnification 0.2 0.6 1.0 1.4 1.8 Graph magnification against di and use the graph to find the focal length of the lens. Homework Equations...

1. Homework Statement - A concave mirror with a focal length of 4.7cm has a 1.8cm object 9.4cm in front of it and i need to know the distance, height, and magnification of the image also i need to figure out how to locate the image by drawing a ray diagram 2. Homework Equations - all i...

Homework Statement A circular concave lens of radius 2 units, has two refracting surfaces described by z=1/2(x2+y2+1) and z=-1/2(x2+y2) What is the volume of the glass? Homework Equations Over a region R: V=\int\int\int dA The Attempt at a Solution I have no idea how to start...

Hi, Does there exist any form for optical lens design? I am a beginner in this field and would like to find such forum, and have search physicsforums.com, but only found isolated threads without any dedicated subforum. Bob

Hello, I have a specific application where I need a custom lens designed to focus an image onto a very small cmos image sensor. So far, I've figured out the general angles of the lense but I need it to be a perfect design before money is put into prototyping it. Here's the specs: The image...

Hi i want to see why the fundamental group of lens space L(p,q) is Z_p. Can you help me?

Homework Statement The picture of a tree on a 35 mm color slide is 1.7 mm high. It is to be projected onto a screen 8.0 m from the slide, and is to appear 559 mm high. a) What focal length lens (in meters) is needed? b) What is the distance in meters between the lens and the slide? c)...

When an object is placed at the focal point of a convex lens, the image is formed at infinity, yet it is called a highly magnified image. The fact being that after passing through the convex lens the rays run parallel or rather as a beam. My question is that if the image is formed at...

What is the pattern made of balls? https://www.youtube.com/watch?v=KrUhKQxOPx0 I have some hypotesis: Something related to the CCD, a diffraction pattern caused by some dirt on the lens, or, but i think it's absurd, the Bravais lattice of the lens? I'm very curious!

Problem concerning zoom lens in camera... This problem deals with a diverging lens placed to the right of a converging lens. The converging lens has a focal length of 12cm and the diverging lens has a focal length of -12cm. The lenses are separated by 4cm. a) For a distant object, where is...

Homework Statement A converging lens of focal length 0.246 m forms a virtual image of an object. The image appears to be .933 m from the lens on the same side as the object. What is the distance between the object and the lens? Homework Equations 1/f = 1/di + 1/do Since the image is...

Hello folks, I am on a project that involves combining Raman microscopy + optical tweezers, and I made a setup over the past year. All of this is home built on minimal funds so its not the neatest of all setups. It involves an upright microscope (coupled to trapping laser) and collecting the...

Homework Statement A light source placed in the focus of a (thin) lens with a focal length of 50mm. A second (thin) lens (with focal length = 400mm) was placed 600mm after the focal point of the first one, an image of the light source was captured at the seonds lens focal point. How...

okay the problem reads -an object 3 cm tall is placed 16 cm in front of a diverging lens with a focal length of 24cm. Find the location and size of the image. What kind of image is it? 1/f = 1/di+1/do hi/ho = di/do I'm not to sure how to solve this i used the equation; 1/f =...

Homework Statement I am working on a project for my cosmology course. I need to determine the Hubble constant from time delay in a gravitational lens. We are using QSO 0957+561 for our data. My question is how do I determine the relevant distances Dl, Ds? I have Dls already. The...

Hi everyone, First time posting, sorry if this is in the wrong format or wrong place. For a project in a cosmology course I need to find the Hubble constant from from time delay in a gravitational lens. the one we are using is QSO 0957+561. My question is how to I find the time delay from...

Ok, I know that the human eye lens adjusts its focal length depending on the object distance to obtain a sharp image on the retina because the image distance has to remain constant. What I am not able to understand is how do the ciliary muscles and the suspensory ligaments contract in order...

Homework Statement I must show that a point source placed at one of the focii will produce a plane wave (or vise versa) when the light is refracted through the interface. This problem is really kicking my ***, I've spent at least three hours trying to figure out different ways to do it...

I have an interestng question. Though sunglasses have curved surfaces-why they have zero power? Can u answer me?

Homework Statement I have an actually interesting practical homework. I need to calculate the optical strength (hope I translated it right, D=1/F), to do I need to find the lens focal length. I need to find my self a concave and a convex lens. I don't have a concave lens (I think), but I do...

Homework Statement A small bulb is placed in front of a convex lens. a) Suppose that the bulb is placed as shown. Using all three principal rays, draw an accurate ray diagram to determine the location of the image. Label the image location...

Homework Statement A double convex lens has a diameter of 5 cm and zero thickness at its edges. A point object on an axis through the center of the lens produces a real image on the opposite side. Both object and image distances are 30 cm, measured from a plane bisecting the lens. The lens has...

Homework Statement An object is at distance s from a thin glass lens of focal length f. The lens is surrounded by air. The image is at distance s' from the lens. Draw a graph of s' versus s. Explain physically why the graph varies as it does. Homework Equations I think I am...

i want to do a project on solar water purification. I just saw a video on purifying water using fresnel lens. However, i haven't found any information on how one can make a fresnel lens suited to the purpose. So, how does one make a fresnel lens?

I will be thankful if the following points are clarified. 1. While deriving the lens formula for a convex lens-say, 1/f= 1/v - 1/u where u and v are the object and image distances, the minus sign is obtained after applying sign conventions. But, I don't understand the logic behind taking the...

Homework Statement There is an object 20 cm from a converging lens with a 10 cm focal length. Homework Equations Is the image upright or inverted? Calculate the image distance. Calculate the image height. The Attempt at a Solution I just had this on a college test in a...

Hi I want to make a high accuracy collimator lens, such that it collimates ( with divergence angle < 1 micron) a beam of light coming from the focal plane but from off axis points as well ( -delta to + delta, where delta is in microns). Sugest some suitable softwares (along with the link)...

Homework Statement A thin plano-convex lens of focal length f is split into two equal halves. One of the halves is shifted along the optical axis as shown. The separation etween the object and the image planes is 1.8m and the magnification of the image formed by one of the half lens is 2...

Homework Statement I must calculate the focal length of a GRIN lens. I.e. a lens which radii of curvature are both infinite. I will consider the refractive index to be varying in function of y (the height in the x-y plane). Say I'm given that at y=0, n(0)=n_0. I'm not sure how to write...

Homework Statement The accomodation power of a boy whose far point is at infinity can vary from 40D to 44D. Using this data find the distance of the retina from the lens. Homework Equations Power of lens,P = 1/f(in meters) f = focal length lens formula, 1/v - 1/u = 1/f The Attempt at...

I'm building a light source for photography and I'm trying to calculate the focal length for a lens that will give me a 40 degree (full width) cone beam from a LED emitter. See attached image. [PLAIN]http://dl.dropbox.com/u/2301/LEDOpticDrawing.jpg The emitter itself measures about 0.5 x...

I just studied the structure of the lens of the eye. And I found out that there are two type of fibres present, which were the Circular Fibres and the Radial Fibres. Can anyone please tell me what is the purpose or function of these two fibres ? Or simply they are just fibres which are...

How to specify a lens to increase angular responsivity of optical sensor? Sensor I presently use has angular responsivity +/-60 degrees at 50% level and I would like to increase it to +/- 80 degrees at 50% level or more. Which lens should I use? Please advice on design guidance for this...

Homework Statement Two 28.0-cm-focal-length converging lenses are placed 16.5 cm apart. An object is placed 36.0 cm in front of one lens. Where will the final image be formed by the second lens? Homework Equations 1/do + 1/di = 1/f The Attempt at a Solution for the first...

Homework Statement (a)How far from a 50.0-mm-focal-length lens must an object beplaced if its image is to be magnified 2.00 x and be real? (b)What if the image is to be virtual and magnified 2.00x? Homework Equations m = -di/do 1/do+ 1/di = 1/f The Attempt at a Solution m...

Homework Statement We have a convex lens with a focal length of 8cm, which is 12cm from the second converging lens that has a focal length of 4cm. An object is 12cm from the first lens. Where is the final image? Homework Equations 1/do + 1/di = 1/f The Attempt at a Solution So...

Homework Statement A transparent film (n = 1.6) is deposited on a glass lens (n = 1.76) to form a nonreflective coating. What is the minimum thickness that would minimize reflection of light with wavelength 500 nm in air? Homework Equations wavelengthXfrequency=c/n (Not sure if that's...

I don't possesses enough knowledge of GR to know if this proposal is feasible (or even remotely possible) I would welcome any constructive criticism of the following idea for detecting Lens Thirring effect: Apparatus consists of a dense, massive sphere or disc, rotating at high velocity...

Homework Statement A biconconvex (n_l=1.5) lens have radii worth 20 and 10 cm and an axial width of 5 cm. Describe the image of an object whose height is 2.5 cm and situated at 8 cm from the first vertex.Homework Equations Transfer matrices. The Attempt at a Solution I used the ray transfer...

Homework Statement What should be the focal distance of a negative thin lens such that there's a virtual image situated at 50 cm from the lens, of an ant at 100 cm from the lens? Given that the ant is at the right side of the lens, localize and describe the image. Homework Equations...

This is just a curiosity question. Are there lens shapes different than just conic sections? Any research or any found applications?

Prove a lens must always be converging if... Consider a single lens with the object on the left side. Prove that for an upright, enlarged image that the lens must always be converging. I'm assuming my professor wants this to be mathematically proven, but I have no idea how to do so...HELP! I...

Homework Statement is the back focal length equal to the front focal length of a thick lens ie a thick plano convex lens? i know it is not but do not know how to clarify it please help Homework Equations The Attempt at a Solution

How can converging lens for sound waves be made? I got confused because i don't which materials should be used to make such lens. The lens if kept in air cannot be made of a solid material as sound travels faster in solid than in air and thus sound would not be converged. I have read that...