Physics Mirrors and Lenses Equations

Radius of curvature

1/f = 1/o + 1/i or 2/r

(f is focal length, o is object distance from mirror, i is image distance from mirror)

Magnification

M = -i/o

If M = 5, will the object appear bigger or smaller?

Bigger

If M is -2, will the object appear to be upright or inverted?

Inverted

In a converging mirror, if o>f (object is farther than focal point), what will the image be?

Inverted and magnified

In a converging mirror, if o=f (object and focal point have same distance), what will the image be?

No image is created; light rays don’t converge

In a converging mirror, if o<f (object is closer than focal point), what will the image be?

Upright and magnified

A diverging mirror will always have an image that is

Virtual, upright, and reduced (shrunk)

Index of refraction

n = cv

(c is speed of light, v is speed in medium)

Myopia (nearsightedness) can be fixed by what type of lens?

Diverging/concave lens, negative power (-D) will diverge light rays

Hyperopia (farsightedness) can be fixed by what type of lens?

Converging/convex lens, positive power (+D) will converge light rays

A convex/converging lens will have what type of r and f?

Positive (+r, +f)

A concave/diverging lens will have what type of r and f?

Negative (-r, -f)

Power (of a lens)

P = 1/f in (D)iopters