Lesson: Images Produced by Thin Lenses Physics • 9th Grade

In this lesson, we will learn how to relate the sizes and positions of objects to images of them produced by thin convex and concave lenses.

Lesson Plan

Students will be able to

recall that the optical power of a thin lens, , equals the reciprocal of the focal length, , of the lens and that the optical power of a lens has the unit of diopters,
recall that the signs of the distance of an object from the center of a thin lens, , and the distance of an image of the object, , from the center of the lens are opposite for distances in opposite directions from the center of the lens,
relate the magnification, , produced by a thin lens to the height of an object, , and the height of the image of the object, , produced by the lens, using the formula ,
relate the focal length of a thin lens to the distances of the center of the lens from an object and from the image of the object, using the formula ,
relate the magnification produced by a thin lens to the distances of the center of the lens from an object and from the image of the object, using the formula .

Lesson Worksheet

Q1:

Which of the following statements most correctly describes how the light rays from an object would have to be aligned with each other for a thin convex lens to form an image of the object at a point that is a distance from the lens equal to the focal length of the lens?

Q2:

A thin convex lens has a focal length of 4.8 cm. The lens is used to form an image of an object and produces a magnification of .

What is the distance from the lens to the image made by the lens?

What is the distance between the lens and the object that makes the image?

Q3:

A thin convex lens is placed at a distance from an object 2.5 cm in height. On the opposite side of the lens, an image of the object is formed 16 cm from the lens. The distance from the object to the image is 36 cm.

Find .

What is the height of the image?