Conceptual Physics Ch. 27- Light Vocab

Photons

massless bundles of concentrated electromagnetic energy

What is the nature of light?

Dual; light is both a particle and a wave

light year

the distance light travels in one year

electromagnetic wave

a wave that consists of oscillating electric and magnetic fields, which radiate outward at the speed of light (can travel through the vacuum of space)

electromagnetic spectrum

All of the frequencies or wavelengths of electromagnetic radiation

infrared light

Infrared light has longer wavelengths, penetrates more deeply, has less energy, and produces more heat than visible light; makes up 60 percent of natural sunlight.

ultraviolet light

part of the electromagnetic spectrum that consists of waves with frequencies higher than those of visible light and lower than those of x-rays

transparent

materials that transmit light

opaque

impossible to see through; preventing the passage of light

ray

a thin beam of light

shadow

An area from which light is blocked.

umbra

The darkest part of a shadow

penumbra

the lighter part of a shadow where light is partially blocked (the fuzzy part)

polarization of light

The property of light describing how the electric and magnetic fields of light waves are aligned; light is said to be polarized when all of the photons have their electric and magnetic fields aligned in some particular way.