Concave Mirror
Definition
A mirror curved inward like a bowl — it can focus light to a point, magnify, or project real images.
Unit: m
Technical definition
A converging mirror with a real focal point in front of its surface. Parallel rays reflect through the focal point (f = R/2). Forms real inverted images of distant objects; magnified virtual images when the object is inside the focal length.
Example
A shaving mirror is concave: hold your face inside the focal length and you see a magnified upright (virtual) image.
Common confusion
Concave mirrors do not always magnify — far objects give small, real, inverted images (like a telescope's primary mirror). Magnification only happens with the object closer than the focal point.