The power of a physician’s eyes is 53.0 D while examining a patient. How far from her eyes is the feature being examined?
This is College Physics Answers with Shaun Dychko. The power of this physician's eye is the reciprocal of object distance plus the reciprocal of object distance. The image distance is the lens retina distance which we're told is two centimeters. And, the power we're told is 53 diopters. And so, we're going to be solving for object distance. And, we'll do that by subtracting one over image distance from both sides and then switch the sides around and we get one over the object distance is power minus one over the image distance. Then, we'll take both sides to the power of negative one, and on the left we take the reciprocal solving for object distance, which is the distance between the lens and the object being observed. And then on the right side, we'll just leave it as it is to the power of negative one. So, that's 54 diopters minus one over two centimeters written as times ten to the minus two meters and all to the negative one, giving us 0.3333 meters, which is 33.3 centimeters.