A microscope has a 12.0x eyepiece and a 59.0x objective lens 20.0 cm apart. What is the focal length in centimeter of the eyepiece? A. 1.26. B. 2.08. C. 2.45. D. 3.19.

What is the power of a lens with 16cm focal length?  A. 1.50D B. 2.00D C. 2.50D D. 3.00D

A biologist changes the objective lens of a microscope, replacing a 20× objective with a 10× objective. To keep the magnification the same, the focal length of the eyepiece mustA. Be doubled.B. Be halved.C. Remain the same.D. The magnification cannot stay the same if the objective power is changed.

4. A convex (converging) lens produces a real, inverted image of an object that is magnified 2.20 times when the object is 37.0 cm from the lens. What is the focal length of the lens? cm

A boy with myopia has an abnormal far point of 80.0 cm. What power of corrective lens is needed to accurately adjust his vision? Neglect the distance between the eye and the corrective lens. a. -2.00 D b. -1.25 D C. -1.75 D d. -1.50 D e. -2.25 D

3. Figure 2.2 is a photograph of an eyeball with the image of a boy in a doorway. Is the eye here acting as a lens or as a mirror? Explain. 6. A stamp collector uses a converging lens with focal length 28 cm to view a stamp 16 cm in front of the lens. (a)Where is the image located? (b) What is the magnification? Figure 2.1 Problem 2 Figure 2.2 Problem 3

7. Two 10.0 cm focal length lenses are placed 20.0 cm away from each other. An object sits 5.00 cm to the left of the first lens. Draw its final image. 8. Two 10.0 cm focal length lenses are placed 20.0 cm away from each other. An object sits 15.00 cm to the left of the first lens. Draw its final image.

1-

Spherical Mirrors: An object is placed 50 cm in front of a concave mirror with a focal length of 25 cm. What is the magnification produced by the mirror? +1.0 +1.5 O-1.0 -2.0 -0.50

An eyeglass prescription that specifies a power of -1.0 diopters is describing a lens that has a focal length of O a. + 1 meter O b.- 100 cm O C. - 1 meter O d. - 1 cm An object placed 25 cm to the left of a +20 cm focal length lens produces a real image 100 cm to the right of the lens. What is the magnification? O a. - 4 Ob. - 0.25 O C. + 2 O d. - 1