What is the focal length of the lens in your eye when you can focus on an object at your near point? Assume that the distance from your lens to the back of your eye is 2.0 cm, that your near point is 21 cm in front of your lens, and that the liquid behind the lens has n=1.00 just like the air in front of your lens.

What is the focal length of the lens in your eye when you can focus on an object at your near point? Assume that the distance from your lens to the back of your eye is 2.0 cm, that your near point is 21 cm in front of your lens, and that the liquid behind the lens has n=1.00 just like the air in front of your lens. (a) 1.8 cm (b) 18 cm (c) 2.1 cm (d) 21 cm (e) None of the above.

It is your first day at work as a summer intern at an optics company. Your supervisor hands you a diverging lens and asks you to measure its focal length. You know that with a converging lens, you can measure the focal length by placing an object a distance ss to the left of the lens, far enough from the lens for the image to be real, and viewing the image on a screen that is to the right of the lens. By adjusting the position of the screen until the image is in sharp focus, you can determine the image distance s′s′ and then use the equation 1s+1s′=1f1s+1s′=1f, to calculate the focal length ff of the lens. But this procedure won'’t work with a diverging lens−−by itself, a diverging lens produces only virtual images, which can'’t be projected onto a screen. Therefore, to determine the focal length of a diverging lens, you do the following: First you take a converging lens and measure that, for an object 20.0 cmcm to the left of the lens, the image is 29.7 cmcm to the right of the lens.…

A lens grinder wants to make a plane-convex lens with the radius of curvature 0.44 m and the focal length 0.8 m. What refractive index should the glass have?