1 / 19

Physics 212 Lecture 28

Physics 212 Lecture 28. Optical Devices. Main Point 1. First, we developed a procedure to determine the image produced by a system of lenses by simply moving through the system one lens at a time, considering the object for a given lens to be the image from the preceding lens. Main Point 2.

idupont
Télécharger la présentation

Physics 212 Lecture 28

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Physics 212 Lecture 28 Optical Devices

  2. Main Point 1 First, we developed a procedure to determine the image produced by a system of lenses by simply moving through the system one lens at a time, considering the object for a given lens to be the image from the preceding lens.

  3. Main Point 2 Second, we introduced a model of the human eye as a converging lens with a somewhat variable focal length. This model was specified in terms of a near point and a far point. We determined the focal lengths of single lenses needed to correct far-sightedness and near-sightedness.

  4. Main Point 3 Finally, we introduced the concept of angular magnification and used it to determine the magnifications of simple telescopes and microscopes.

  5. System of Lenses Image from first lens Becomes object for second lens • Trace rays through lenses, beginning with most upstream lens

  6. System of Lenses Image from first lens Becomes object for second lens • Virtual Objects are Possible !!

  7. Checkpoint 1 Two people who wear glasses are camping. One of them is nearsighted and the other is farsighted. Which person’s glasses will be useful in starting a fire with the sun’s rays? A. The farsighted person’s glasses B. The nearsighted person’s glasses

  8. Checkpoint 2 A person with normal vision (near point 28 cm) is standing in front of a plane mirror. What is the closest distance to the mirror the person can stand and still see herself in focus? A. 14 cm B. 28 cm C. 56 cm

  9. A parallel laser beam of width w1 is incident on a two lens system as shown below. Checkpoint 3 Each lens is converging. The second lens has a larger focal length than the first (f2 > f1). What does the beam look like when it emerges from the second lens? A. The beam is converging B. The beam is diverging C. The beam is parallel to the axis with a width < w1D. The beam is parallel to the axis with a width = w1E. The beam is parallel to the axis with a width > w1 A B C D E

  10. Normal Eye

  11. Far-sighted Converging Lens creates virtual image at person’s near point

  12. Near-sighted Fix with diverging lens that creates virtual image at far point.

  13. Multiple Lenses Exercises Two converging lenses are set up as shown. The focal length of each lens is 47 cm. The object is a light bulb located 70 cm in front of the first lens. • What is the nature of the image from the first lens alone? • REAL (B) REAL (C) VIRTUAL (D) VIRTUAL • UPRIGHT INVERTED UPRIGHT INVERTED

  14. Suppose we now decrease the initial object distance to 58 cm. Applying the lens equation, we find s1’ = 2.48m • What is the object distance s2 for lens 2? • s2 = -0.48 m (B) s2 = +0.48 m (C) s2 = -2.48 m (D) s2 = +2.48 m (E) s2 = +2.58 m • What is the nature of the FINAL image in terms of the ORIGINAL object? • REAL (B) REAL (C) VIRTUAL (D) VIRTUAL • UPRIGHT INVERTED UPRIGHT INVERTED

More Related