A camera lens used for taking close-up photographs has a focal length of 55.0 mm. The farthest it can be placed from the film is 33.0 mm. What is the closest object that can be photographed? answer choices a)8.25 cm b)3.30 cm c)6.60 cm d)5.08 cm

A converging lens made of crown glass has a focal length of 15.0 cm when used in air. If the lens is immersed in water, what is its focal length? (a) negative (b) less than 15.0 cm (c) equal to 15.0 cm (d) greater than 15.0 cm (e) none of those answers

A group of students is given two converging lenses. Lens A has a focal length of 12.5 cm, and lens B has a focal length of 50.0 cm. The diameter of each lens is 6.50 cm. The students are asked to construct a microscope from these lenses that has the same magnification as the telescope in Problem 80 if possible, and they have this discussion: Avi: These are the same lenses we used to make a telescope. So they wont work as a microscope. Microscopes are for looking at close objects; telescopes are for looking at far objects. Cameron: All you need for a microscope are two converging lenses. I think the difference from a telescope is just that the order of the lenses is switched. A microscope is just a backward telescope. Shannon: I think the order of the lenses doesnt matter because the magnification is inversely proportional to both focal lengths. I think we have to adjust the distance between the lenses. a. What do you think? b. If a microscope can be constructed with these two lenses, describe its design. What is the minimum separation of the lenses? Where must you place the object?

A particular nearsighted patient cant see objects clearly beyond 15.0 cm from their eye. Determine (a) the lens power required to correct the patients vision and (b) the type of lens required (converging or diverging). Neglect the distance between the eye and the corrective lens.