law of conservation of energy
energy can be neither created nor destroyed, but it can be converted from one form to another
the number of wavelengths passing a fixed point in one unit of time, usually a second (Hz)
relationship between energy of light and frequency
the higher the frequency, the higher the energy; the lower the frequency, the lower the energy
why does refraction occur
the speed of light is affected by the density of the medium; light travels slower in the denser medium. As light passes into the denser medium, it bends toward the normal. On exiting to the less dense medium, it bends away from the normal, so the incident beam and the transmitted beam are parallel.
light reflected from a smooth surface. The observed beam appears to be reflected in one direction only giving the surface a shiny appearance
light reflected from a rough surface. Light is scattered in many directions, giving the surface a dull appearance. The angle of incidence must still equal the angle of reflection, but the rough surface creates many normals to the surface.
A colored object absorbs all wavelengths except those corresponding to the color it appears. Light of that color is reflected.
results from the removal of certain wavelengths of reflected light by absorption.
subtractive mixing process
start with white light, use blue, red, and green filters to remove particular wavelengths.
the extent to which white (or black or gray) is mixed with a pure hue; sometimes called purity