Magnification

Definition

Magnification is the measure of how much larger or smaller an image is compared to the object itself. It is given by the ratio of the image height to the object height.

5 Must Know Facts For Your Next Test

1. Magnification ($M$) can be calculated using the formula $M = \frac{h_i}{h_o}$, where $h_i$ is the image height and $h_o$ is the object height.
2. For lenses, magnification can also be expressed as $M = -\frac{d_i}{d_o}$, where $d_i$ is the image distance and $d_o$ is the object distance.
3. A positive magnification indicates an upright image, while a negative magnification indicates an inverted image.
4. If $|M| > 1$, the image is larger than the object; if $|M| < 1$, the image is smaller than the object.
5. Magnification does not have units because it’s a ratio of two lengths.

Review Questions

• How do you calculate magnification using image and object heights?
• What does a negative magnification value indicate about an image?
• If an object has a magnification of 3, what can you say about its size relative to its actual size?

Related terms

Focal Length:

The distance from the center of a lens to its focus point.

Image Distance: The distance between the lens and the formed image.

Object Distance: The distance between the lens and the object being viewed.