TA: Keslo Estil SEC#: Name:
Lab 11. Mirrors, Lenses, Telescope
Lenses and mirrors are the basic building blocks of such optical instruments as cameras, binoculars, telescopes, microscopes, magnifying mirrors, movie projectors, etc. In this lab, the basic properties of lenses and mirrors will be investigated. In the last part of the experiment you will construct and examine the properties of an astronomical telescope. Throughout the lab, you will be using the lens/mirror formula:
where f, is the focal length of the mirror or lens, s is the distance from the object to the lens or mirror (object distance), and s’ is the distance from the lens or mirror to the image (image distance). The magnification, M, of an image created by a lens or mirror is given by
where h and h’ are the object and image heights, respectively.
Objectives
· Measure the focal lengths of mirrors and lenses.
· Clarify what is the difference between real and virtual objects and images.
· Construct an astronomical telescope and measure its magnification.
Preliminary Question (1-3)
Analysis (1-8)
Note: Show all equations, calculations and very clear screenshot of the graph with fit to receive full credit.
Data Tables
| Table 1 Mirror | |
| Radius of curvature of mirror = 20 cm | Focal length of mirror = 10 cm |
| Magnification = 1 |
| Table 2 Converging Lens | |||
| Object distance, s (cm) | Image distance, s’ (cm) | 1/s (cm)-1 | 1/s’ (cm)-1 |
| 20 | 20 | ||
| 25 | 17 | ||
| 30 | 15 | ||
| 15 | 31 | ||
| 12 | 45 |
Slope of graph:
Intercept of graph:
Focal length from intercept:
Focal length from distant object = 10 cm
| Table 3 Diverging Lens | |
| Image distance for lens A = 15 cm | Object distance for lens C = -5 cm |
| Image distance for lens C = 8 cm | Focal Length of lens C = |
| Table 4 Telescope | |
| Focal length of lens A = 10 cm | Focal length of lens B = 40 cm |
| Theoretical angular magnification
= |
Measured magnification = |
