# lenses

1. ### Focal length of converging thin lens graphs

I tried -M=pq = f/(f-p) = f/f - f/p = 1-(f/p) => M+1= -f/p => -Mp-p=f But since it’s the y intercept, p will equal zero and so the focal length will be 0?
2. ### Calculate the focal length of the spectacle lens

1. Homework Statement A hyperopic eye has a near point of 1.10 m. Calculate the focal length of the spectacle lens required to correct the hyperopia (assume that the near point of the normal eye is 25.0 cm.) 2. Homework Equations 1/f=1/p+1/q 3. The Attempt at a Solution I just used .25 m...
3. ### What is the power of the lens in diopters?

1. Homework Statement It is desired to magnify reading material by a factor of 3.5× when a book is placed 9.5 cm behind a lens. What is the power of the lens in diopters? 2. Homework Equations 1/f = 1/di + 1/do M = -di/do P=1/f 3. The Attempt at a Solution I set equal the magnification to...
4. ### Contact Lenses Optics Problem (Two-Parts)

I believe I have answered the first question correctly (although I am not certain of this). And I'm struggling with grasping how to approach the second part of the question. Any guidance or recommedations on reading material would be greatly appreciated. 1. Homework Statement Contact lenses...
5. ### Physics Lens Problem

1. Homework Statement An object and its lens-produced real image are 2.4 m apart. Part A If the lens has 55-cm focal length, what are the possible values for the object distance? Express your answer using two significant figures. 2. Homework Equations 1/s+1/s'=1/f s-s'=2.4m 3. The Attempt...
6. ### B Lenses for laser

I want to make a laser to burn paper so if i use 2 or 3 convex lenses with a laser will it be helpful . Or can i use 1convex then 1 concave and then 1convex to make it
7. ### Magnification, when is it negative?

1. Homework Statement In magnification, I keep on confusing the signs. From what I understand currently, magnification is positive when the image is erect. An image is only erect when it is a virtual image, therefore virtual images = positive magnification. Vice versa, magnification is negative...
8. ### Ultraviolet Laser Beam Shaping With Constraints

1. Homework Statement 2. Homework Equations Lens equation 1/f = 1/d_o + 1/d_i Minimum Gaussian beam spot 2*w_0 = ((4 * lamda * F)/(pi * D)) Where: w_0 = beam waist (half beam diameter) lambda = wavelength F = focal length of lens D = diameter of incoming spot Don't forget to match...
9. ### B Plano convex lenses and focal length

Does the orientation of a plan convex lens affect it's focal lenght? If I put il like in the first example in the photo and makeep the calculation using the lens maker equation I get f positive What happens if I turn the curved face on the right? Using the lens maker equation now the radius...
10. ### Insights New High Performance Ultra-wide Angle Lenses - Comments

Andy Resnick submitted a new PF Insights post New High Performance Ultra-wide Angle Lenses Continue reading the Original PF Insights Post.
11. ### Compound lens separated by a distance

1. Homework Statement 2. Homework Equations We will call $s$ the distance of the object from the first lens, $s'$ the distance of the image from the first lens and $s''$ the distance of the image from the second lens. The Gauss's lens equation: \frac{1}{s}...
12. ### Lenses Problem

1. Homework Statement The question is : https://postimg.org/image/lntyejfvp/ [Broken] 2. Homework Equations 1/s +1s' =1/f 3. The Attempt at a Solution Hello, I have an upcoming test on Monday on lenses and while reviewing I've come across a question that confused me. My understanding is...
13. ### Calculate the focal length of a planoconvex lens?

1. Homework Statement Calculate the focal length of a planoconvex lens that produces a real image 2.5 times as big as the object if the object is 2.5 cm from the lens? 2. Homework Equations The only one I can think of is 1/f = 1/v + 1/u 3. The Attempt at a Solution My 'attempt' is 1/f =...
14. ### Why image is blurry or focused with convex lenses?

1. Homework Statement I have a few fundamental questions in optics about the focus and blurry images. Each text book says that according to this picture the object image is the same. 1) If we move the screen to point further then the image will be blurry. What causes it to be blurry? 2) Why...
15. ### Finding focal point of concave lens using concave and convex

1. Homework Statement I was doing this experiment. Let's look at this image: Suppose we get the imaginary object at dv by convergence lens. And this object is like a real object for the concave lens. Then how do we get a real object on the screen? It is known that only virtual objects can...
16. ### I Lens System for windows

Hi everyone, I am working on a project on my final project in Product design. The project is about translating digital concept into the analogue world. In my project I am especially interested in the digital “Windows” and am trying to apply the functions and possibilities of digital on to...
17. ### B Help with lenses for hand-made telescope

I'm trying to make a handmade telescope, but I'm stuck with the lenses I bought 2 lenses. they are the same "convex from one side and concave from the other side" like glasses lenses. then I knew that I need a double convex for both the object lens and the eyepiece lens. so I decided to put the...
18. ### I Identifying the length of the object on the image

Hello First of all, I was told this is a physics problem. If it's incorrect, I apologize. I have an image I want to know the length of the black ship (the ship which is carrying a ship). Lets assume that I know the length of the text on the ship (I have a reference object). Is this...
19. ### Fermat's Principle to explain lenses and mirrors

How do we use Fermat's principle of least time to explain the required shapes of lenses and mirrors?
20. ### Dispersion and the dependences of refractive indexes

I'm revising for a uni exam with past exam papers, and have gotten stuck on the details of dispersion. The two exam questions prompting this are a) What is the physical reason why the index of refraction for blue light is bigger than that of red light? and b) Explain how dispersion makes a...
21. ### Light Intensifier

1. I am supposed to create a device that can intensify the light directed at a light intensity sensor. A small light bulb will be 25 cm away from the light sensor. My device is required to be 20cm long and placed in between the light bulb and the light sensor in order to make the light that is...
22. ### Stargazing Problem in making a small refracting Telescope

It sounds silly to ask such question or stumble in such problem, indeed! But I was willing to make some small telescopes for young friends of mine, to encourage them to delve in the skies. So, I bought: 1. Double concave, spherical glass lens, with a focal length of approx. -75mm and diameter...
23. ### Diverging and Converging lenses in a system

1. Homework Statement A)Find the final position of the image (from the object, I assume?) B)Find the size of the final image of the object. 2. Homework Equations 1/f = 1/do + 1/di 3. The Attempt at a Solution 1) Solved first distance: 1/5 - 1/4 = 1/di --> 4/20 - 5/20, di = -20cm 2) Use...
24. ### Lens Question for Design of an Infrared Spotlight

Hello All. I'm working on a project to build an infrared spotlight which will hopefully light up a distant object so that I can see it on an IP enabled night vision camera. The lens problem seems very straight forward, but I could use some help. Per the attached diagram, I want to focus the...
25. ### Can't find any micrograph for glass

I can only find micrographs (photographs of microstructure under electron microscope) of non-transparent glasses. Is it impossible top be able to see the internal structure of a transparent material? If anyone can tell me what I'm doing wrong or find me one that would be great! I'm looking...
26. ### Microscope magnification with camera

I have two lenses for my microscope. The object lens which magnifies 63 X. Then there is my eyepiece lens with f=100 mm which focuses the incoming light at an camera. How can I calculate the total magnification? All calculations so far for the eyepiece involve the 25 cm of the human eye, but now...
27. ### Finding the focal length of a negative lens without another lens.

1. Homework Statement A simple method for determining the focal length of a negative lens is shown below. Prove this is true. 2. Homework Equations 3. The Attempt at a Solution The linear magnification formula relates magnification, the distance from the lens to the image (i), the...
28. ### Very small holographic laser projectors and diffraction.

In thinking about what it would take to make a feasible invisibility cloak or holographic disguise or perfect hologram room, I've imagined something that works like this: A light beam "image" is projected onto a device designed to refract or reflect it in all directions, but only 1 color in any...