(a) What is the maximum angular magnification of an eye-...

Name: Problem 26, Chapter 25: College Physics
Uploaded: 2020-04-03T15:11:21-08:00
Duration: 1 min 28 s
Channel: Netra Sharma
Description: (a) What is the maximum angular magnification of an eye- glass lens having a focal length of 18.0 cm when used as a simple magnifier? (b) What is the magnification of this lens when the eye is relaxed?

(a) What is the maximum angular magnification of an eye- glass lens having a focal length of 18.0 cm when used as a simple magnifier? (b) What is the magnification of this lens when the eye is relaxed?

Key Concepts

Image Location (Relaxed Eye Condition vs. Maximum Magnification)

In optical devices like a simple magnifier, the image location relative to the eye significantly affects the perceived magnification. When the final image is at infinity (the relaxed eye condition), the angular magnification is given by the ratio of the near point to the focal length of the lens. For maximum magnification, the device is arranged so that the final image appears at the near point, leading to a higher magnification value. This distinction is essential in understanding and calculating the performance of magnifying instruments under different viewing conditions.

Simple Magnifier

A simple magnifier, often using a single convex lens, is an instrument that creates an enlarged, virtual image of an object. By positioning the object appropriately with respect to the lens, the angular size of the image is increased compared to the object’s size when observed by the unaided eye, thus enhancing the detail that can be seen.

Angular Magnification

Angular magnification is the measure of how much larger an object appears when viewed through an optical instrument compared to viewing with the naked eye. It is defined by the ratio of the angle subtended by the image at the eye to the angle subtended by the object at the unaided eye, indicating how effectively the device increases the apparent size of the object.

Near Point of Distinct Vision

The near point of distinct vision is the closest distance at which the human eye can comfortably focus on an object, typically assumed to be about 25 cm for an average eye. This distance is crucial in optical design and magnification calculations as it serves as a reference for determining the maximum angular enlargement that can be achieved under ideal viewing conditions.

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