Lens Definition and 836 Threads

Hi all, This is probably a silly questions, but I want to be sure :). I'm wondering if a real image, created by a convex lens, can appear larger than the lens diameter itself. As an example, I'm thinking about the following: - I have a an object of height h_0=7.76" (display size of...

Homework Statement A 3 cm tall object is placed 11 m from a wall. If the image is to be projected upside down with a 20 cm focal lense, what is: A} The type of lens used? B] Where is the lens placed? C] What is the height of the image? D] What is the magnification of the...

Does anyone know how the machining tolerance in the construction of an electromagnetic lens affects resolution in a scanning electron microscope?

Homework Statement An object is placed on the optic axis and in front of a converging lens of focal length 38 cm such that its image size is 1.5 times the object size. Calculate the distance of the image from the lens. Express your answer in centimeter. Homework Equations 1/f=1/di +...

Hi I have a laser beam(engraving laser machine) and then use a lens for focus the beam but my lens has a crack on the center of lens and when i use my laser in high power the beam diameter will bigger and burning area zone is bigger so: 1- Does the crack doesn't let the maximum focus?in law or...

Hello, I'm working with an automotive headlamp and I was asked to simulate a projection of this lamp onto a wall 25 feet apart. I know I need to use a Fresnel lens as a collector to achieve this, however I have many questions: 1. How should I choose the right Fresnel lens? 2. I need to...

In the context of anti-reflective coatings put on glasses lenses, I recently read, "No light reflecting means more light in through the lens - energy must be conserved after all."? How does MORE light get in? The best I could imagine is either: 1. That by using destructive interference on...

If we are imaging light in the far field region. We have three situations/relations (illustrated below): Arc Length: We know the distance subtended (S) by the light ray in a lens-less system will be proportional to R (distance to the screen) and theta; simple, especially if theta is very...

What is a determinium lens and where I can buy it online? Thank you

I have been studying Fourier Optics and I have a basic conceptual question. I understand the mathematics of how to perform Fourier Transforms however the part of this topic I seem to have missed is why the action of a lens on light is the same as performing a Fourier Transform on the functional...

Homework Statement Hi all. This is a problem from one of the problem sheets from earlier in the term. I'm just revising for my exam tomorrow and can't solve this one. Here it is: Consider a light source placed at a fixed distance L from a screen, such that a lens of focal length f can be...

Hello everyone, A friend of mine came up with this question in class and I really do not have a good answer. Suppose you have a convex lens that has been cut in half horizontally and the top half removed. The question is: Will the bottom half of the lens still form an image? I really...

Homework Statement When an object is placed 69.0cm from a certain converging lens, it forms a real image. When the object is moved to 39.0cm from the lens, the image moves 19.0cm farther from the lens. Find the focal length of this lens. Homework Equations 1/do + 1/di = 1/fThe Attempt at a...

Homework Statement A real object is placed 9.00 cm from a converging lens that has a focal length of 24.0 cm. The image is________. My classmate answered "14.4 cm from the lens, virtual, and enlarged," but apparently this is incorrect. I solved it out and chose the option "14.4 cm from the...

Homework Statement A biology student wishes to examine a bug at a magnificaiton of +5.00 by looking through a single lens. the student wants the image of the bug to be a distance of 25cm from the lens. what is the focal length of the lens? Answer:+6.25cm Homework Equations...

I'm looking at concentrating light (e.g. sunlight) with a lens, and trying to figure out the maximum concentration I can get. If you have a perfectly collimated source, a lens can focus that light down to a point, but when the source has some divergence, the point you can focus down to will have...

Hi, I'm using an aspheric lens with a LED light source for a DIY projector. As I understand it, if I place the led light source at the focal length of the aspheric lens, the light should be collimated(parallel) coming out the other side. As I decrease the distance between the led and the...

Homework Statement A lens is designed to work in the visible, near-infrared, and near-ultraviolet. The best resolution of this lens from a diffraction standpoint is Options: a.) the same for all wavelengths. b.) in the near-ultraviolet. c.) indeterminate. d.) in the near-infrared. e.)...

Homework Statement 1. An object is placed 1.5m in front of a convex lens of focal length 500mm. Find the position of the image formed and state its nature. 2. A second convex lens of focal length 25mm is placed 770mm behind the first convex lens. Find the position of the final image formed and...

Hi Guys, I have a question about a telecentric lens I've been studying and was wondering if you guys could help clear some cobwebs in my head. For starters, I am simplifying the TC lens as a compound lens. Also, this lens has 2 degrees of freedom: (1) it can be extended and retracted (2) it...

Hi All, I need help determining focal length value in a two lens system. In the set up, the light source (object) is within a tube, a medium surrounds it with refractive index n1=1.52. The end of the tube is met with a curved convergent surface, the center of which is 0.635 cm away and focal...

Homework Statement An object is placed 400 mm in front of a convex lens of focal length 80 mm. Find the position of the image formed. State the nature of this image. A second concave lens of focal length 25 mm is placed 80 mm behind the first convex lens. Find the position of the final...

Homework Statement For my high school physics coursework I must investigate factors affecting the focal length of a lens. I have focused on radii of curvature and completed my data collection and verified the accuracy using the lens makers equation. However, in the conclusion I am really...

Homework Statement A +15 cm focal length lens and a flat mirror are 45 cm apart (the mirror is to the right of the lens and can be treated as a concave mirror with an infinite focus length). There is an intermediate image 30 cm to the right of the lens (15 cm to the left of the mirror) with...

I was just wondering if a person wearing convex lenses looks at a light source... Will excess heat be generated in his eyes? As it is a converging lens.. Thanks!

Homework Statement My physics coursework hypothesis: "As the thickness of the lens increases, the focal length decreases". I tested this using a ray box, a stand to hold lenses and a screen to see where the light is most focused, which is then measured with a metre ruler. The distance 'u'...

Homework Statement An object is placed 2.4m from a screen, and a lens of focal length f is placed between the object and the screen so that a real image of the object is formed on the screen. When the lens is moved 1.2m toward the screen, another real image of the object is formed on the...

I googled for lens formula's proof on the internet and found one here http://www.tutorvista.com/content/physics/physics-ii/light-refraction/convex-lens-formula.php The problem is that during the course of derivation, it is assumed that image distance is -u following the sign convention...

Hello. I'm looking for a lens that can collimate (or focus far away >500mm ) a light coming out from a LED. before I give more details is this even possible? Thanks.

Dear All, I need you kind support in a problem, which I am unable to figure out. It is regarding thick lens. I am determining lens principal planes and radius using shaping factor and focal length. The forward problem I am using is, Focal length 1/f = (n-1)*[1/r1 - 1/r2...

lens -- What physical features makes a lens thin? What physical features makes a lens thin? How can you differentiate one lens from the other based on their thickness? What is the measure of their thickness?

Optics -- magnification of a converging lens Homework Statement Dioptry of converging lens is $D=3$. What is magnification ##u##? Homework Equations The Attempt at a Solution ##\frac{1}{f}=D## - dioptry. \frac{1}{f}=\frac{1}{p}+\frac{1}{l} u=\frac{l}{p} l=up...

Homework Statement A convex mirror with a focal length of -20 cm is 18 cm from a convex lens whose focal length is 6.0 cm. An object is located between them, 10 cm from the mirror and 8.0 cm from the lens. The object will produce two images, one from the light which just goes through the...

So we are learning the lens formula and I have two textbooks, my school textbook and another one that is much more detailed. My school textbook gives the lens formula as:- 1/f=1/v-1/u while the other one gives 1/f=1/v+1/u (v is image distance and u is object distance) There both different! I...

Homework Statement General question here: If I have a lens that looks like two concave lenses put together (I believe it is called a Meniscus), how do I conceptually tell whether the lens should be converging or diverging? I think I remember reading something saying that it depends upon which...

Homework Statement Trying to find the number of diffraction maxima and the width of the whole pattern. \lambda = 500nm b = 2.8μm (Slit Width) f = 100mm r = 25mm L = 25mm (Slit to Lens) Homework Equations I have the worked out the irradiance formula as: I(\theta)=I_0...

I'd like to know why a ray of light passing through the optical center of a convex lens does not get refracted at all. According to my knowledge, a ray of light will not get refracted if the angle of incidence is zero i.e. it is along the normal. With this in mind, I see how a ray traveling...

Homework Statement Optical System: Biconcave lens and convex mirror separated by distance 'L'. Object placed 0.40m in front of the lens. Final image is .12m from the vertex of the mirror Lens curvature radii: 0.10m and 0.20m Mirror curvature radii: .12m Calculate the distance 'L'Homework...

optics, the resulting power of the lens...?? a thin lens , made of refractive index 1.5,has a front surface +11 d power and back surface -6d ..if this lens is submerged in a liquid of refractive index 1.6, the resulting power of the lens is... a)-1 dioptre b)+1 dioptre c)-5 dioptre...

Any help much appreciated - this is driving me crazy! Homework Statement Show that the focal length of a half ball lens, in air, (in the paraxial limit) is given by: f=R/n-1 Homework Equations Equation (from Hecht- Optics), for refraction at a spherical interface: nm/s0 + nl/s1...

Homework Statement A certain lens focuses light from an object 2.90m away as an image 46.9cm on the other side of the lens. 1. What type of lens is it? (Converging or Diverging?) 2. What is the focal length? 3. Is the image real or virtual? Homework Equations 1/di + 1/do = 1/f...

Homework Statement Parallel rays of green mercury light with a wavelength of 546 nm pass through a slit covering a lens with a focal length of 60.0 cm. In the focal plane of the lens the distance from the central maximum to the first minimum is 10.2 mm. What is the width of the slit...

Homework Statement You have paid big bucks to see The Bourne Legacy at the 3-D IMAX theater in Vancouver. Just before the movie is about to begin, the theater staff tell you that the lens for the projector has just broken! You really want to see the movie and decide that it should be simple to...

Homework Statement A 2.0--tall candle flame is 2.1 m from a wall. You happen to have a lens with a focal length of 37 cm . How many places can you put the lens to form a well-focused image of the candle flame on the wall? For each location, what are the height and orientation of the...

I was solving the following problem, and I've got confused at the second question http://img407.imageshack.us/img407/7921/43545856.png 1) An object is put at the center of curvature C of a convergent lens. Where is the image? Calculate by gauss equation. It's obvious that the image is in...

The question can be found here: http://gyazo.com/fc4d26cd35e6ce368ad2a8ed504f1dcc The refractive index it references can be found here: http://gyazo.com/94fd2f3b5ea7da9226c3acd56b0024c1 I'm not really sure where to get started on the "showing" part of the question. I anticipate that Snell's...

Homework Statement A converging lens with a focal length of 14.2 cm is used to inspect a coin. The lens forms a virtual image 30.1 cm away. What is the magnification? Homework Equations (1/Si) + (1/So) = (1/f) M = (hi/ho) = (-Si/So) The Attempt at a Solution 1/So = 1/f - 1/Si...

The cartesian sign convention for a convex lens is follows: 1. All distances on the principal axis are measured from the optical center. 2. The distances measured in the direction of incident rays are positive and all the distances measured in the direction opposite to that of the incident...

Hi, I'm Chaitanya, 4th year undergraduate student in biomedical engg. I have an idea of making a mobile phone application which measures the power of your spectacle glasses. The idea is we take an image with the phone's inbuilt camera. One of the spectacle lens will be held in front of the...

http://www.sciencedaily.com/releases/2012/08/120824093523.htm If I understand the technology correctly these optical antennas substitute surface plasmon effects for the phase delays of the light passing through glass. They also use standard semiconductor manufacturing techniques meaning mass...