1. How far from the lens must the film in a camera be, if the lens has a 35.0 mm focal length and is being used to photograph a flower 75.0 cm away? Explicitly show how you follow the steps in the Problem-Solving Strategy for lenses.

2.

a. A doctor examines a mole with a 19.0 cm focal length magnifying glass held 16.0 cm from the mole Where is the image?

b. What is its magnification?

c. How big is the image of a 3.10 mm diameter mole?

3.

a. A camera with a 50.0 mm focal length lens is being used to photograph a person standing 3.50 m away. How far from the lens must the film be?

b. If the film is 36.0 mm high, what percent of a 1.76 m tall person will fit on it? (You do not need to enter any units.) (Discuss how reasonable this seems, based on your experience in taking or posing for photographs.)

4.

a. A certain slide projector has a 65 mm focal length lens. How far away is the screen, if a slide is placed 67.0 mm from the lens and produces a sharp image? b. If the slide is 24.0 by 36.0 mm (width and height), what are the dimensions of the image?

5.

a. A camera lens used for taking close-up photographs has a focal length of 26.0 mm. The farthest it can be placed from the film is 34.8 mm. What is the closest object that can be photographed?

b. What is the magnification of this closest object?

6.

a. Suppose your 58.0 mm focal length camera lens is 59.9 mm away from the film in the camera. How far away is an object that is in focus?

b. What is the height of the object if its image is 1.80 cm high?

7.

a. What is the focal length of a magnifying glass that produces a magnification of 2.50 when held 4.00 cm from an object, such as a rare coin?

b. Calculate the power of the magnifier in diopters.