Chapter 25, Problem 1CQ

A lens is used to examine an object across a room. Is the lens probably being used as a simple magnifier? Explain in terms of focal length, the image, and magnification.

To determine

If the lens used to examine an object across the room is a simple magnifier.

Explanation of Solution

As the near point of the eye is $25\text{cm}$, the maximum angular magnification is,

$m_{\max }=1+\frac{25\text{cm}}{f}$

• $f$ is the focal length of the lens

When observed through a simple magnifier, the object will be magnified by a factor given by the equation.

Conclusion:

Thus, the lens used to examine an object across the room is a simple magnifier.