Images in Mirror and Lenses

General terms for forming images from lenses:

Images are:

• Real if they occur on the opposite side of the lens as the object. (R)
• Virtual if they occur on the same side of the lens to the object. (V)
• Upright if they are the same way up as the object. (U)
• Inverted if they are upside down. (I)
• Diminished if they are smaller than the object. (D)
• Magnified if they are larger than the object. (M)

General terms for forming images from mirrors:

Images are:

• Real if they occur on the same side of the lens as the object. (R)
• Virtual if they occur on the opposite side of the lens to the object. (V)
• Upright if they are the same way up as the object. (U)
• Inverted if they are upside down. (I)
• Diminished if they are smaller than the object. (D)
• Magnified if they are larger than the object. (M)

Note: Most terms are identical for lenses and mirrors except for real and virtual images.

Diagrams:

Drawing diagrams for lenses and mirrors is done to illustrate the magnitudes of various features. The features that are usually illustrated include: = the distance between the object and the lens/mirror. = the distance between the image and the lens/mirror. = the height of the object. = the height of the image. = the focal length of the lens/mirror. = the magnification of the image.

Equations:

The position and nature of the image formed by a lens is calculated using the lens formula: The size of an image can be determined using the formula for magnification. Magnification is a ratio of the image to the object: The following allows you to play around with a lenses and images.

Images formed by refraction in a convex lens: Images formed by refraction in a concave lens: Images formed by reflection in a concave mirror: 