Chapter 30, Problem 21A

What will happen to the image projected onto a screen by a lens when you cover most of the lens?

To determine

The effect on the image projected onto a screen by a lens when most of the lens is covered.

Explanation of Solution

Introduction:

An image is formed when the incident rays converge at a point or appear to diverge from a point after the incident rays leave the lens.

Light is incident on a lens at all angles and on all the points on the surface of the lens. These incident rays converge at a point or appear to diverge from a point forming an image. When most of the lens is covered, some of the rays still fall on the lens surface and would form the image. However, given the smaller number of rays contribute in forming the image, the intensity of the resulting image will be very less.

Conclusion:

Image will be formed but with very less intensity.