Score PHYSICS I LENSES PROBLEMS Solve the following problems using the examples given in your Lenses hand out. Show all steps of all formulas! Calculations may be done in pencil, but answers in the blanks should be in ink. Remember: NO NAKED NUMBERS! 1. Eric and Ben find a discarded plastic lens lying on the beach. The boys discuss what they learned in Fizix last smester and argue whether the lens is a converging or a diverging one. When they look through the lens they notice that objects are inverted. A) If an object sitting 25.0 cm in front of the lens forms an image 20.0 cm behind the lens, what is the focal length of the lens? B) Is it a converging or diverging lens? (6 pts) 1A. 1B 2. Sarah looks at Nicole's face through a diverging lens. A) If Nicole's face is 50.0 cm from the lens that forms an image at a distance of 20.0 cm, what is the focal length of the lens? B) Is the image Sarah sees a real image or a virtual image? C) Draw a ray diagram of the situation. (11 pts) 2 A. 2B.3. Girogio is clicking shots of the fashion model Nadine as she walks toward him across the studio. Girgio's camera contains a lens with a focal length of 0.050 m. A) How far back must the film be located when Nadine is 3.0 m from the camera? B) Should the lens be moved in or out as Nadine approaches closer to the photographer? C) Draw ray diagrams of the situation with Nadine at 3.0 m and 1.0 m from the camera. (16 pts ) 3 A 3B 4. MS Mitchell is showing slides to her biology class. A) If the slides are positioned 15.5 cm from the projector lens which has a focal length of 15.0 cm, where should the screen be placed in order to produce the clearest image of the slide? B) Draw a ray diagram of the situation. (10 pts) 4 A. 5. Matt is out on a safari. Looking through his telescope, he spots a giraffe in the distance. The telescope has an objective lens of 40 cm focal length and an eypiece of 2 cm focal length. A) What is the magnification of the giraffe? B) How large is the image formed by the telescope if the giraffe appears to be 1.5 cm high to the naked eye? (10 pts) 5 A. 5 B6. Erica, an entomologist, studies a millepede that she holds behind a magnifying glass which has a focal length of 2.0 cm. A) Assuming Erica's near point is 25.0 cm, what is the angular magnification? B) Does she need to bring the magnifying glass closer to or farther from the millipede in order to make it appear larger? (6 pts) 6 A. 6B 7. Mr. Robinson, a jeweler, looks through his jeweler's loupe (That's a small magnifying glass attached to his glasses.) in order to read the engraving on a pewter bowl. The loupe has a focal length of 3.0 cm. If Mr. Robinson's near point is 24 cm, what is the angular magnification of the engraving? (5 pts) 7