Which magnification compares the ratio of the object size to the image size formed by an optical system?

Which magnification compares the ratio of the object size to the image size formed by an optical system?

• A. Lateral magnification
• B. Angular magnification
• C. Object magnification
• D. Image magnification

Answer: (A)

The key idea is how an optical system scales the size of what you see. This is captured by lateral (transverse) magnification, which is the ratio of the image height to the object height. It tells you how much bigger or smaller the image is compared with the object, and for a thin lens it’s written as M = h_i / h_o. A negative sign means the image is inverted relative to the object, though often we refer to the magnitude |M| when orientation isn’t important. For example, if an object of 2 mm height forms an image of 6 mm height, the lateral magnification is 3, meaning the image is three times larger. Angular magnification, by contrast, concerns how large the image appears in the eye’s field of view, not its linear size on the image plane. Object or image magnification aren’t standard terms for this size-relationship.

The key idea is how an optical system scales the size of what you see. This is captured by lateral (transverse) magnification, which is the ratio of the image height to the object height. It tells you how much bigger or smaller the image is compared with the object, and for a thin lens it’s written as M = h_i / h_o. A negative sign means the image is inverted relative to the object, though often we refer to the magnitude |M| when orientation isn’t important. For example, if an object of 2 mm height forms an image of 6 mm height, the lateral magnification is 3, meaning the image is three times larger. Angular magnification, by contrast, concerns how large the image appears in the eye’s field of view, not its linear size on the image plane. Object or image magnification aren’t standard terms for this size-relationship.