Question
t Ill Glossary Unit I1I G is towet Projeet 4 Page 2 of 11 Each of your e channging the fees! length you are ble to focus on ar, object based how far away Vt Is erom you. For this problem you will determine th maximum focal length of your erve. r your eyes has a lens i in it. This lens can change s shape and hence its focal ength, By A. To determine the maximum focal length of your eye you need to establish how far you can see under ideal conditions (no fog, an unobstructed line of vision). Bear in mind that hvow far you can see ts not the same as what distance an object is visible at. You may not be make out a pen a mile away from you but you can easily make out a mountain at hat distance, when it comes to discerning objects, the size of the object matters. Which of the following objects is the furthest away? O Pluto O Halley's Cepet O The Sun Any star (besides the Sun) O The Moon O Mars State how far away the object is. This will be your object distance. crmm 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 maximum focal length of your eye. Also determine the magnification for this situation. FOCAL LENGTH MAGNIFICATION cm http:/www.webassign.net/web/Student/Assignment-Responses/submit?dep-10652416
Explanation / Answer
Nearest star = proxima centauri (distance) = 4.242 light years (source wikipedia)
so distance = 4.242 x 3 x 108 x 86400 x 365 = 4.013 x 1016m (note: you can take any star of your choice)
so u = 4.013 x 1016m and v = 1.7cm = 0.017m
so 1/f = 1/u + 1/v = 58.823.
so f = 1/58.823 = 0.017m = 1.7cm. (note: since u is so large, 1/u approaches zero, so v ~ f)
