Optics: Concave and Convex Mirrors and Lenses Key Concepts

Concave mirror: object beyond C (2f)

Real, inverted, reduced, between C and F.

Concave mirror: object at C (2f)

Real, inverted, same size, at C.

Concave mirror: object between C and F

Real, inverted, enlarged, beyond C.

Concave mirror: object at F

No image; rays parallel, image at infinity.

Concave mirror: object between F and mirror

Virtual, upright, enlarged, behind mirror.

Convex mirror: object anywhere

Virtual, upright, reduced, behind mirror.

Converging (convex) lens: object beyond 2f

Real, inverted, reduced, between f and 2f (opposite side).

Converging (convex) lens: object at 2f

Real, inverted, same size, at 2f (opposite side).

Converging (convex) lens: object between f and 2f

Real, inverted, enlarged, beyond 2f (opposite side).

Converging (convex) lens: object at f

No image; rays parallel, image at infinity.

Converging (convex) lens: object inside f

Virtual, upright, enlarged, same side as object.

Diverging (concave) lens: object anywhere

Virtual, upright, reduced, same side as object.

Mirror focal length: concave vs convex

Concave = positive f; Convex = negative f.

Lens focal length: converging vs diverging

Converging (convex) = positive f; Diverging (concave) = negative f.

Image distance (di) positive when?

Mirrors: real image (in front). Lenses: real image (opposite side).

Image distance (di) negative when?

Mirrors: virtual image (behind mirror). Lenses: virtual image (same side).

Magnification sign positive means?

Upright image.

Magnification sign negative means?

Inverted image.

Magnification formula?

M = -di/do = hi/ho.

Mirror/Lens equation?

1/f = 1/do + 1/di.