Two converging lenses having focal lengths of f 10.7 cm and f, = 20.0 cm are placed d = 50.0 cm apart, as shown in the figure below. The final image is to be located between the lenses, at the position x = 28.7 cm indicated. fi Object Final image (a) How far (in cm) to the left of the first lens should the object be positioned? 16.48 Your response differs from the correct answer by more than 10%. Double check your calculations. cm (b) What is the overall magnification of the system? -1.85 Your response differs from the correct answer by more than 10%. Double check your calculations.

Minimum focal length of your eye Each of your eyes has a lens in it. This lens can change its shape and hence its focal length. By changing the focal length you are able to focus on an object based on how far away it is from you. For this problem you will determine the minimum focal length of your eye. A) Hold an object out in front of you at arm's length. Close one eye and bring the object towards your eye and determine how close it can be to your eye and still be in focus. 25 cm ✓ B.) The average human eye has an image distance of 1.7 cm. In other words, it is 1.7 cm from the lens in your eye to the retina. Using this information and your answer to (A), determine the minimum focal length of your eye. Also determine the magnification for this situation. min 6 x Units are required for this answer. M = 8 X C.) The lens in your eye creates an image. It is this image that the rods and cones in our eye actually detect. Regarding the image your lens created when finding the minimum focal…

Cotion Two converging lenses having focal lengths of f₁ = 10.5 cm and f2 = 18.0 cm are placed a distance d = 52.5 cm apart as shown in the figure below. The image due to light passing X through both lenses is to be located between the lenses at the position x = 30.5 cm indicated. fi f2 Object Final image position 5.1 a) At what value of p (in cm) should the object be positioned to the left of the first lens? Selected Answer: 8.42 Response Feedback: Pay attention to the reference position when converting object distance for the second lens to the image distance for the first lens.

nnip Priv Practice Problems - 3 The left end of a long glass rod of index 1.6350 is ground and polished to a convex spherical surface of radius 2.50 cm. A small object is located in the air and on the axis 9.0 cm from the vertex. Find (a) the primary and secondary focal lengths, (b) the power of the surface, (c) the image distance, and (d) the lateral magnification. Solve Prob. 3.1 graphically. (a) Find the image distance by the oblique-ray method 1. (b) Find the relative size of the image by the parallel-ray method. The left end of a water trough has a transparent surface of radius -2.0 cm. A small object 2.5 cm high is located in the air and on the axis 10.0 cm from the vertex. Find (a) the primary and secondary focal lengths, (b) the power of the surface, (c) the image distance, and (d) the size of the image. Assume water to have an index 1.3330. A hollow glass cell is made of thin glass in the form of an equiconcave lens. The radii of the two surfaces are 1.650 cm, and the distance…