Lenses Definition and 321 Threads

How would you go about solving a problem involving a lens moving at relativistic speeds, or an object being relativistic being viewed through a lens? instead of coming up with a specific problem, does anyone know what happens to lens' focal length and such as its velocity becomes large? not so...

I'm in the middle of studying for the MCAT, and just want to get all the concepts instead of memorizing how to solve problems. I'm having a hard time understanding converging lenses. From what I understand, converging lenses create real images that are inverted. This property of inversion...

Hi there! I wonder if anyone could explain to me exactly how the optics of Luneburg lenses work? Are there any major losses due to diffraction, spill-over etc? Is it possible to focus just one image using this lens? Thanks, Jean

Let's say that there are three lenses A (all of which are semicircles: flat on one side, curved on the other). One lense is a short and curved D, another lense is a very elongated and narrow D (longer than the first lense), and the third lense is as long as the second lense but has a sharper...

Let's say that there are three lenses A (all of which are semicircles: flat on one side, curved on the other). One lense is a short and curved D, another lense is a very elongated and narrow D (longer than the first lense), and the third lense is as long as the second lense but has a sharper...

The focal length of a relaxed human eye is approximately 1.78 cm. When we focus our eyes on a close-up object, we can change the refractive power of the eye by about 16 diopters. Calculate the focal length of the eye when we focus closely. 1/di+1/do=1/f im not really sure what to...

Homework Statement Hey, I was just doing some questions on thin lenses, and thought of a question I really want answered just can't find anything on in the text or anywhere. So the question involves a lens with a focal length of f = 18.18 cm now the question asks if the lens would be...

1. Are all convex lenses also converging lenses? The attempt at a solution Convex refers to shape. Converge refers to action. My answer is yes, provided that the material the lens is made of is denser than air, or denser than some other surrounding medium. Am i correct? OR are there other...

Homework Statement a candle is placed 36cm from a screen. where between the candle and the screen should a converging lens with a focal length of 8.0cm be placed to produce a sharp image on the screen? Homework Equations 1/focal length = 1/distance of object from lens + 1/distance of...

Homework Statement The lens and mirror in the figure below have focal lengths of +74.0 cm and -59.1 cm, respectively. An object is placed 1.00 m to the left of the lens as shown. http://www.jmlproductions.net/jmlproductions/p36-54.gif I need to find the final image location. Homework...

Hi everyone, You can call me kwen & I've got a question which has been on my mind for some time now. ~ All my life I've been studying with full-powered glasses (perfect vision) and I understand that in the long run, that's not very good for the eyes due to the strain it puts on them...

1. A nearsighted person wears contacts with a focal length of -7.6cm. If this person's far point distance with her glasses is 8.7m, what is her uncorrected far point distance? 2. 1/F=1/do+1/di 3. 1/-7.6=1/do+1/870 =-7.534 I am completely lost here...please help. Thanks!

Homework Statement 2 thin lenses separated by 10cm. First has a focal length of 20cm, the second has a focal length of 30cm.Homework Equations Lens transfer matrix for each lens: \begin{bmatrix} 1-\frac{D_2d_{21}}{n_{t1}} &-D_1-D_2+\frac{D_1D_2d_{21}}{n_{t1}} \\ \frac{d_{21}}{n_{t1}} &...

Homework Statement Here is the layout of 2 lenses: -----------------(1)------------(2)-------------I-------------- Two thin lenses, numbered 1 and 2, with the intermediate image "I" is to the right of one of the lenses. The distance between the lenses is lettered d. Both lenses have...

Homework Statement a) In the autocollimation experiment of Sec. 3.5, a thin convex lens is placed 25 cm from a pinhole that acts as a point source of light. A plane mirror placed 20 cm behind the lens reflects the light back through the lens, and the reflected light forms a sharp spot beside...

Heyy this is my first time on here and I'm only doing first year physics so my understanding might not be up to scratch =/ I'm doing a practical on thin lenses where we have to do a various amount of measurements and calculations to do with convex lenses. However I'm not very confident with...

Hi, We have an optical equipment that has a narrow entrance slit, on the other end of the narrow entrance slit two rod lenses are exposed. They are getting dirty for various reasons. Does anybody know of any handheld air/vacuum cleaning with thin nozzle that can penetrate the slit and even...

any idea what these ball lenses are.. ? any specific application?

Homework Statement the question is attached The Attempt at a Solution ok so a and b i can do but c), i donts know whether my answer is right and I am a little confused about the conceptual idea... so first thing i did was found the radius of curvature using the lens maker equ...

A converging lens with f=33.7 cm yields an image with magnification M=−2. Find the object distance. Give your answer ... * in terms of centimeters. Do not include units in your answer. They will be assumed to be cm...

Hi. There's a question that has given some variables which am not sure how to compute to some previous lens/optics equations. These are not the actual variable values by the way. If a projector (square pixel SXGA) has a diagonal size of 5 mm which uses a screen of 1 m in which the distances...

Lenses and optics: solving for focal point. (SOLVED) (2 points, penalty of 0.5) When a flower pot is placed 1.2 meters on the left of a magnifying glass (converging lens), an image is formed on a screen 0.37 meters to the right of the lens. Find the focal length of the lens. Give your answer...

1. A diverging lens with a focal length of -14 cm is placed 12 cm to the right of a converging lens with a focal length of 18 cm. An object is placed 33cm to the left of the converging lens. Where will the final image be located. 2. 1/f = 1/di + 1/do dob = L - dia 3. After solve...

Homework Statement Anne is farsighted; the nearest object she can see clearly without corrective lenses is 2.4 m away. It is 1.8 cm from the lens of her eye to the retina. What should the focal length of her contact lenses be so that she can see clearly objects as close as 24.0 cm from...

Homework Statement As shown in the diagram below (not to scale), a 3.0 cm high object is placed 50.0 cm from thin converging lens A that has a focal length of 10.0 cm. Converging lens B with a focal length of 15.0 cm is placed 25.0 cm to the right of lens A. Find and describe the final...

Homework Statement Could someone explain to me about the near point and the far point in the eye because I'm confused about the 25 cm for the near point and infinity for the far point. Also, like in problems like this: What eyeglasses would you prescribe for persons with the following...

Homework Statement The focal length of a diverging lens is -20 cm. Locate the object, given that the image is real, erect, and 150% of the size of the object. Homework Equations (1/f)=(1/do)+(1/di) M=-(di/do) The Attempt at a Solution i'm not really sure how a diverging lens forms a...

Hi, I'm new to this place, and I'm not sure if my problem fits with this forum, but I'll give it a try. Right now, I'm building a laser range finder, but my biggest concern will be focusing the reflected laser beam onto a small silicon photodiode. And to add to that, I have barely any...

When I'm given do, ho, and hi. How would i solve for di Normally i would do -di/do = hi/ho and cross-multiply but I'm not sure how the negative comes into effect. do = object distance di = image distance ho = object height hi = image height If... ho = 3cm hi = 4cm do = 5cm...

What if two converging or diverging lenses were placed side by side, in contact with each other. Where would be the image formed for the converging lens, would it be to the right of the lens combined or to the left? Why? Also, where would it be if both lens were diverging? thanks!:)

Path Difference in Lenses... A convex lens will converge all rays parallel to the optical axis to the focus. Now obviously different rays at different distances from the optical axis will travel different distances in reaching the focus. So why does this not create any path difference between...

Why if two concave and convex lenses are nested together, will there be no resulting convergence or divergence if their focal lengths are the same, but if the concave lens has a larger focal length the rays will converge slightly? What is (are) the mathematical equation(s)/reason(s)?

Homework Statement A converging lens has a focal length f, and a diverging lens has a focal length –f, which has the same magnitude as the converging lens. They are separated by a distance D which is greater than f, as shown. Parallel light enters from the left. Will the light be brought...

Homework Statement Heres the problem exactly as written: A system of lenses is composed of three lenses. Calculate the maximum magnification these three lenses will achieve if the lenses are located 35.0 cm apart. The lenses have focal lengths of 15.0, 20.0, and 25.0 cm.Homework Equations 1/p...

I was reading on the f-number of lenses for cameras...somewhere in the text, they stated that the area of the image is proportional to q2, in which q is image distance. I figured the area to be proportional to q, but I don't really see it as q2...so how does this work out?

hello members of www.physicsforums.com ! primarily i want to apologize for the double thread post; i posted another thread at this link: https://www.physicsforums.com/showthread.php?p=1950906#post1950906 and i am afraid it was homework and i did not see the homework section so please forgive...

The statement is that the image formed by the 1st lens acts as the object for the 2nd lens. For 2 thin lenses aligned along a common axis, would this statement be true for when the image formed by the 1st lens is real and past the 2nd lens (while ignoring the effect of the 2nd lens in this...

Homework Statement A simple camera telephoto lens consists of two lenses. The objective lens has a focal length f1 = +36.0 cm. Precisely 33.0 cm behind this lens is a concave lens with a focal length f2 = -10.0 cm. The object to be photographed is 3.67 m in front of the objective lens. (a)...

I was reading on thin lenses, in which the lens makers' equation was proved. The proof first gave the lens (a biconvex lens) a thickness (which it would later consider negligible) so that the light would pass through one surface and out the other (so it comes into contact with 2 surfaces). The...

Homework Statement There are 2 lenses separated by 5 cm. Very far to the left of the first lens is an object (the distance of the object from lens one is NOT given). The focal length of lens 1 is 20 cm and the focal length of lens 2 is 10 cm. Where is the image due to the first lens? State the...

I was reading a bit on thin lenses when a postulation was made that the image formed from the first surface would be the object for the second. The postulation made sense for when the first image is virtual, but I don't see how it works when the first image is real? Can anyone provide me the...

Hello, here is my question: if an object position can only tend to infinity, without ever reaching it (since infinity is just an abstraction), its image will tend to appear on the back focal plane of a converging lens, without ever forming there. The image will always be created on the image...

Homework Statement An object is 18cm in front of a diverging lens that has a focal length of -12cm. How far in front of the lens should the object be placed so that the size of its image is reduced by a factor of 2.0? Homework Equations 1/do + 1/di = 1/f m= -di/do The Attempt at a Solution...

have absolutly no idea where to put this but ill put it here My eyesight is something like +6.25/+6.50 Now the eye man (optomotrist?) said that they only make contact lenses that go up to +6. I was wondering why this is? Also why can't long sighted people have laser eye sugery? Is there...

Homework Statement the figure shows a combination of two identical lenses. There is a 2cm tall object that is 36 cm away from the first lens (f=9 cm). The second lens is 15 cm away from the first lens. It also has a focal length of 9 cm. So, the first question was "find the position of the...

Homework Statement A lens is made of glass for which the refractive index is n[r]=1.5 for red beams and n[v]=1.52 for violet beams. radii of both surfaces are the same and equal R=1m. Find the distance between foci for red and violet beams Homework Equations The Attempt at a Solution

Homework Statement Two lenses, one converging with focal length 20.0cm and one diverging with focal length -10.0cm, are placed 25.cm apart. An object is placed 60.0cm in front of the converging lense. Determine the position of the final image. Homework Equations \frac{1}{s_i} +...

Homework Statement For each of the following object positions in front of a converging lens, suggest at least one practical application. (E.g. overhead projector, camera etc.) a) Between the lens and F' b) At F' c) Between F' and 2F' d) At 2F' e) Beyond 2F' The Attempt at a...

Hi, I need to build a telescope for my physics class. I need to use any 3 lenses(converging or diverging) and 1 mirror. I was thinking of using an achromatic telescope design for that. However I am not sure what kind of lenses to use and whether I should make the eyepiece from two lenses or just...

1. An object is placed in front of a converging lens in such a position that the lens (f = 11.0 cm) creates a real image located 27.0 cm from the lens. Then, with the object remaining in place, the lens is replaced with another converging lens (f = 19.0 cm). A new, real image is formed. What is...