A lens produces an image on a screen that is twice as large as the object. If the image is located15.7 ?? from the lens. (a) Determine the object distance. (b) Find the focal length of the lens.(c) What type of lens was used in this case?

A microscope has an objective lens with a focal length of 16.22 mm and an eyepiece with a focal length of 9.28 mm. With the length of the barrel set at 35.0 cm, the diameter of a red blood cell's image subtends an angle of 1.43 mrad with the eye. If the final image distance is 35.0 cm from the eyepiece, what is the actual diameter of the red blood cell? Hint: To solve this equation, go back to basics and use the thin-lens equation. um

An object of height 5.50 cm is placed 33.0 cm to the left of a converging lens with a focal length of 10.5 cm. Determine the image location in cm, the magnification, and the image height in cm. HINT (a) the image location in cm cm (b) the magnification (c) the image height in cm cm (d) Is the image real or virtual? O real virtual (e) Is the image upright or inverted? O upright O inverted

An object is placed 30 cm from the center of a 50-cm-focal-length converging lens. (a) Draw a ray diagram and show where the image is located. (Your diagram MUST  be legible and correct to earn points).  (b) Find the location of the image analytically using the thin lens equation. (c) What is the magnification? (Pay attention to the signs).

A measurement indicates that a patient cannot clearly see any object that lies closer than 60.8 cm to the patient's eye. (a) Which of the following terms best describes this distance? far pointnear point    magnificationfocal length (b) The patient needs to be able to clearly see objects that are just 24.0 cm distant. A contact lens is made to order. What focal length (in cm) should this lens have? Assume the lens can be modeled as an ideal thin lens, which lies adjacent to the eye.  cm (c) What is the power, P, of the contact lens (in diopters)?  diopters

The projection lens in a certain slide projector is a single thin lens. A slide 23.0 mm high is to be projected so that its image fills a screen 1.90 m high. The slide-to-screen distance is 3.06 m. (Enter your answers to at least one decimal place.) (a) Determine the focal length of the projection lens. mm(b) How far from the slide should the lens of the projector be placed to form the image on the screen? mm