Ray Optics and Optical Instruments

A concave mirror converges parallel paraxial

A concave mirror converges parallel paraxial rays to a real focus and has negative focal length by sign convention, while a convex mirror makes parall

Distances measured in the direction

Distances measured in the direction of incident light are positive, and distances measured opposite to it are negative. Heights above the principal ax

Refraction is the change in direction

Refraction is the change in direction of light when it passes between transparent media. Snell's law is sin i / sin r = n21, where n21 is the refracti

For a spherical interface between two

For a spherical interface between two media, the relation is n2/v - n1/u = (n2 - n1)/R. It connects object position, image position, refractive indice

The lens maker's formula is 1/f

The lens maker's formula is 1/f = (n21 - 1)(1/R1 - 1/R2). For a thin lens, the image relation is 1/v - 1/u = 1/f. A convex lens has positive focal len