Name: ______
Chapter 18 Calculations Practice – Alternate Assignment
1. A student views an image of a vase in a plane mirror. The apparent height of the vase’s image is 15 cm and the image appears to be 32 cm behind the mirror. (a)How tall is the actual vase and (b)how far in front of the mirror is the vase?
2. A convex lens with a focal length of 15.1 cm is used to form an image of an object placed 59.0 cm from the lens. The height of the object is 42.1 cm. Calculate the (a)size and (b)distance of the image that is formed. (c)Also, is this a real or virtual image?
3. The lens of a certain movie projector has a focal length of 23.50 cm. When a frame of film is in place, it is 18.55 cm from the lens. (a)At what distance from the lens would you place a screen in order to receive a focused image? (b)If the image on the film is 32 mm high, how tall is the image formed on the screen? (c)Is it a real or virtual image?
4. Since 1838, the diameter of dimes minted in the United States has been standardized at 15.9 mm. A magnifying lens that has a 155-mm focal length is used to view a dime. If the dime is placed 55.6 mm from the lens, (a)what is the size and (b)distance of the image? (c)Is the image real or virtual?
5. The lens of a magnifying glass forms a 26.0-mm image of a 3.5 mm insect when the insect is placed 13 mm from the lens. What is the focal length of this lens?
6. A student views a tree that is 23.2 m tall through a concave lens that has a focal length of -50.0 cm. If the tree is 42.0 m away, (a)how tall is the image of the tree? (b)Is this image real or virtual?