Final answer:
To determine the maximum distance at which a person can read letters based on their visual acuity, we apply the concept of similar triangles and optics, using the proportion of the letters' physical size to the size of the image on the retina.
Step-by-step explanation:
Visual acuity can be defined as the sharpness of vision, measured by the ability to discern letters or numbers at a given distance according to a fixed standard. A person with normal acuity can see objects clearly that correspond to specific retinal image sizes. In the given scenario, a person can see clearly objects that form an image 4.00 µm high on their retina. To find out the maximum distance at which this person can read 75.0 cm high letters, we apply the concept of similar triangles, as the physical size of an object and its image on the retina form such triangles with the optical system of the eye.
The maximum distance can be calculated using the proportion between the size of the letters and the size of the image they form on the retina. The formula to calculate the distance (D) is given by D = (size of letters × distance to retina) / size of retinal image. Since the size of the retinal image is 4.00 µm, by substituting the given values and converting 75.0 cm to micrometers (750000 µm), we can find this maximum distance. This approach demonstrates the practical application of optics in understanding how the eye interprets visual information.