ANALYTICAL PHYSICS 2B, CHAPTER 1 ADDITIONAL PROBLEMS

1. Light in vacuum is incident on the surface of a glass slab. In the vacuum the beam makes an angle of 32.0o with the normal to the surface, while in the glass it makes an angle of 21.0o with the normal. What is the index of refraction of the glass? ANSWER: 1.48 2. In the figure, a ray of light is perpendicular to the face ab of a glass prism (n = 1.52). Find the largest value for the a angle  so that the ray is totally reflected at face ac if the prism is immersed (a) in air and (b) in water.  ANSWER: (a) 48.9o; (b) 29.0o b 3. A concave shaving mirror has a radius of curvature of 35.0 cm. It is positioned so that the (upright) image of a man's face is 2.50 times the size of the face. How far is the mirror from the face? ANSWER: 10.5 cm 4. A concave mirror has a radius of curvature of 24 cm. How far is an object from the mirror if the image formed is (a) virtual and 3.0 times the size of the object, (b) real and 3.0 times the size of the object, and (c) real and 1/3 the size of the object? ANSWER: (a) 8.0 cm; (b) 16 cm; (c) 48 cm 5. A movie camera with a (single) lens of focal length 75 mm takes a picture of a person standing 27 m away. If the person is 180 cm tall, what is the height of the image on the film? ANSWER: 5.0 mm 6. An object is 4.00 cm in front of a converging lens. The magnification of the enchilada is -2.00. What is the focal length of the lens?

7. A lens is made of glass having an index of refraction of 1.5. One side of the lens is flat, and the other is convex with a radius of curvature of 20 cm. (a) Find the focal length of the lens. (b) If an object is placed 40cm in front of the lens, where will the image be located? ANSWER: (a) +40 cm; (b)  8. An eraser of height 1.0 cm is placed 10.0 cm in front of a two-lens system. Lens 1 (nearer the eraser) has focal length f1 = -15 cm, lens 2 has f2 = 12cm, and the lens separation is d = 12cm. For the image produced by lens 2,what are (a) the image distance i2 (including sign), (b) the image height, (c) the image type (real or virtual), and (d) the image orientation (inverted relative to the eraser or not inverted)? ANSWER: (a) + 36 cm; (b) 1 .2 cm; (c) real; (d) inverted 9. A coin is placed 20 cm in front of a two-lens system. Lens 1 (nearer the coin) has focal length f1 = + 10 cm, lens 2 has f2 = +12.5 cm, and the lens separation is d = 30 cm. For the image produced by lens 2, what are (a) the image distance, (b) the overall lateral magnification, (c) the image type (real or virtual), and (d) the image orientation (inverted relative to the coin or not inverted)? ANSWER: (a) -50 cm; (b) 5.0; (c) virtual; (d) inverted 10. Two thin lenses of focal lengths f1 and f2 are in contact. Show that they are equivalent to a single thin lens for which the focal length is (f1.f2)/(f1 + f2).