Fascinating Facts About Focal Length and Angular Magnification

What is the relationship between focal length and angular magnification in a magnifying glass?

Given that a person with a near point at 28 cm uses a certain magnifying glass that produces an angular magnification of 7.0 with the image very distant.

What is the focal length of the lens of this magnifying glass?

Answer:

The focal length of the lens of a magnifying glass with specified angular magnification is 4 cm.

When a person with a near point at 28 cm uses a certain magnifying glass that produces an angular magnification of 7.0 with the image very distant, we can determine the focal length of the lens using the formula for angular magnification:

Angular magnification = Near point of magnifying glass / Focal length

By making the focal length the subject of the formula, we get:

Focal length = Near point of magnifying glass / Angular magnification

Substitute the values given:

Focal length = 28 cm / 7 = 4 cm

Therefore, the focal length of the magnifying glass is 4 cm. This relationship between focal length and angular magnification plays a crucial role in understanding the optics of magnifying glasses and other optical devices.