and

are

axis

beam

bus

close

closeup

concav

concave

convergence

convergent

converging

convex

curvature

cut

distance

focal

focusing

formation

has

image

lamp

length

light

macro

magnification

magnifying

mirror

mirrors

object

old

optics

orange

out

path

physics

piece

plane

point

projector

radius

real

reflection

safety

school

shape

shiny

slide

spherical

stop

surface

the

there

travel

two

types

virtual

which