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

In this worksheet, we will practice relating the sizes and positions of objects to images of them produced by thin convex and concave lenses.

**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?

- AThe light rays from the object would have to be parallel to each other.
- BThe light rays from the object would have to be emitted in all directions.
- CThe light rays from the object would have to be converging on a point.
- DThe light rays from the object would have to be diverging from a point.

**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?

**Q4: **

An image of an object 1.5 cm in height is formed by a thin lens. The magnification produced by the lens is .

Is the lens convex or concave?

- AConvex
- BConcave

What is the height of the image?

**Q5: **

A thin lens, lens A, has twice the optical power of another thin lens, lens B. Lens A has a focal length of 21 cm. What is the focal length of lens B?

**Q6: **

A thin lens has a power of 4.5 diopters. What is the focal length of the lens?

**Q7: **

Which of the following formulas correctly relates 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?

- A
- B
- C
- D
- E

**Q8: **

An object is placed 2.5 cm from a thin convex lens with a focal length of 3.75 cm. The object is then moved away from the lens.

What is the initial distance between the object and the image?

What is the initial magnification produced by the lens?

How far would the object have to be moved for the lens to produce the same magnification that it produced initially, but with the image now real and inverted?

What is the distance between the initial image formed and the inverted image formed?

**Q9: **

A thin convex lens is placed 15 cm away from an object. On the opposite side of the lens, an image of the object is formed that is 4.2 cm in height due to a magnification by the lens of .

What is the distance from the lens to the image?

What is the height of the object?

**Q10: **

A thin convex lens with a focal length of 2.1 cm is placed 4.5 cm away from an object. On the opposite side of the lens, an image of the object is formed. What is the distance from the lens to the image?