two lenses Definition and 23 Threads

  1. Skaiserollz89

    A Fourier optics model of a 4f system

    In my system I am trying to represent two lenses. L1 with focal length f1=910mm and the other lens, L2 with focal length f2=40mm. These lenses are space such that there is a distance of f1+f2 between the lenses. I have a unit amplitude plane wave incident on L1. My goal is to find the...
  2. nish95

    Final Image position for a setup with two lenses

    First image is an object for the concave lens so won't +ve direction change from right to left?! In that case, object distance will be -ve (from concave lens towards right side). Any ideas? Solution in the book takes first image's distance to be +ve. See attached ray diagram for clarification...
  3. M

    Finding the Image Location for Two Lenses in Contact

    Homework Statement Two lenses with the focal length of 50 mm are placed tightly. An object is placed 130 mm away from the lenses. Where is the image generated by the lenses? Homework Equations \frac{1}{a}+\frac{1}{b}=\frac{1}{f} L = f_{ocular} + f_{objective} The Attempt at a Solution...
  4. S

    Emergent light produced by two lenses

    Homework Statement Two thin lenses are placed 5 cm apart along the same axis and illuminated with a beam of light parallel to that axis, The first lens in the path of the beam is a converging lens of focal length 10 cm whereas the second is a diverging lens of focal length 5 cm. If the second...
  5. tensor0910

    Two lenses: find Di through second lens

    Homework Statement A 1.60 cm tall object is 20.0 cm to the left of a lens with a focal length of 10.0 cm . A second lens with a focal length of 36.0 cm is 44.0 cm to the right of the first lens.Homework Equations 1/f = 1/di + 1/do , hi/ho = di/doThe Attempt at a Solution [/B] calculate...
  6. P

    Equivalent focal length of two lenses

    Homework Statement Two thin lenses have focal lengths of -5cm and +20cm. Determine their equivalent focal lengths when (a) cemented together and (b) separated by 10cm. Homework Equations ##\frac{1}{f_{eq}}=\sum_{n=1}^k \frac{1}{f_n}## The Attempt at a Solution So the first part was easy since...
  7. N

    If two lenses have the same radii of curvature but different indexes

    Homework Statement If two lenses have the same radii of curvature but different indexes of refraction their focal lengths won't be equal because the one with the greater index of refraction will undergo greater refraction and will have a smaller f. Doesn't this contradict the definition of...
  8. H

    Can a converging lens become a diverging lens in liquid?

    Homework Statement (a)Can a converging lens be made to diverging if it is placed into a liquid? (b)What if?What about a converging mirror? Homework Equations Homework Equations The Attempt at a SolutionThe Attempt at a Solution (a)Let the focal length of the converging lens be...
  9. A

    Power of Two Lenses: Find d & l

    Homework Statement Design a thin-lens telephoto lens with a back focal distance of 50 mm and an effective focal length of 200 mm, and a maximum system length (distance between first lens and image) of 100 mm. Find the power of each of the two lenses. (Lenses are in air.)Homework Equations...
  10. C

    Calculating Image Position and Height Using Two Lenses?

    Homework Statement A 2 cm tall object is 20 cm to the left of a lens with a focal length of 10 cm. A second lens with a focal length of 15 cm is 30 cm to the right of the first lens. Calculate the image position and height. Compare with ray-tracing. Homework Equations 1/f = 1/do + 1/di, m =...
  11. H

    Solving Two Lenses Problem: Ray Diagrams & Equations

    Homework Statement Extracted from NSS Physics at Work Book 3A, a textbook published by Oxford University Press. An object O is placed at distance u from the optical centre of convex lens A. The focal length of the lens is f1, where f1 > u. An image I' is formed. (b) Another convex lens B is...
  12. M

    Virtual Image Location for Negative Lens System?

    Homework Statement S is a lighted object, height=1. what is the final image that is created by the system? Homework Equations The Attempt at a Solution i just don't understand how do i find the location of a virtual image created by a negative lens when the rays converge to a...
  13. B

    Calculating Distance and Magnification for Two Lenses | Homework Example

    Homework Statement I don't have the exact problem, but I have a sample that I made demonstrating my question: There are two lens, the first of focal length 20cm and the second of focal length 25cm. the image is located 15cm in front of the first lens, and the distance between the two lens...
  14. L

    What is the focal length of the second lens in an afocal system?

    Homework Statement An object at a distance a1 in front of a convex lens with the focal length f1 is imaged at a distance b1. A second lens at the distance d from the first lens with the focal length f2 is then imaging this Image with the image distance b2. a) Give the image distance b1 as...
  15. F

    What should be a very simple optics question is giving me problems (two lenses)

    I'm studying for the GREs, and I ran across this problem: Object located at x=0 Lens 1 located at x=40cm Lens 2 located at x=70cm (30cm from lens 1) f1 = 20cm f2 = 10cm Both lenses are converging, thin lenses. So I have to find the final image location. The understanding I have of multiple...
  16. X

    Optics - Two lenses touching each other with oil inbetween

    Homework Statement Two identical, thin, plano-convex lenses with radii of curvature of 15 cm are situated with their curved surfaces in contact at their centers. The intervening space is filled with oil of refractive index 1.65. The index of the glass is 1.50. Determine the focal length of...
  17. zimo

    Two lenses problem, multiple interpretations, no true answer

    Homework Statement Two lenses, with 20cm focals are in 1m distance from each other. A body is located 60cm from the right lens.Homework Equations I figured that the relevant equation should be: \frac{n1}{u} + \frac{n2}{v} = \frac{n2 - n1}{r} but perhaps a I'm wrong. The Attempt at a Solution...
  18. K

    Solving Two Lenses In A Row Homework Problem

    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} +...
  19. R

    Focal Lengths of Two Lenses of a Microscope

    A microscope is made in a tube 25.0 cm long. It magnifies 5.00 x 102 times, 50.0 times by the objective lens and 10.0 times by the eyepiece. What are the focal lengths of the two lenses?
  20. R

    How Does Lens Placement Affect Image Height and Orientation?

    A 1.5-cm tall object is placed 0.50 m to the left of a diverging lens with a focal length of 0.20 m. A converging lens with a focal length of 0.17 m is located 0.08 m to the right of the diverging lens. What is the height and orientation with respect to the original object of the final image...
  21. M

    Combinination of two lenses, converging and diverging

    Homework Statement A converging lens and a diverging lens, separated by a distance of 30 cm, are used in combination. The converging lens has a focal length of 15 cm. The diverging lens is of unknown focal length. An object is placed 19 cm in front of the converging lens; the final image is...
  22. S

    Calculating Refractive Power of Two Lenses Combination

    hey- I've been working on this one for quite some time now and just can't seem to get it: Two converging lenses with focal lengths 10 cm and 20 cm are placed 30 cm apart. Rays from a very distant object are impinged on the lens system parallel to the principal axis. What is the refractive...
  23. S

    An object and two lenses - Is this right?

    ok have a look at the pdiagram i drew the thing in the middle is a convex thin lens and to the right is a concave mirror. The arrow on the left stands for the object, the object is placed at 2F1. The convex lens to cancave mirro length is 2(f1 + f2) Find the location of the nature and...
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