Electromagnetic Spectrum, Colour Theory, and Light Sources

Vocabulary flashcards covering wave properties, electromagnetic radiation types, additive and subtractive colour theories, and light source definitions.

Natural Light

Light produced naturally by the Sun or other stars.

Artificial Light

Light produced by human technology, such as incandescent, fluorescent, or LED lights.

Incandescent Light

Light produced by an object containing metal at high temperatures (e.g., a regular lightbulb).

Fluorescent Light

Light emitted by substances when exposed to electromagnetic light, such as a lightbulb containing mercury gas.

Phosphorescent Light

Light emitted by phosphor substances only when exposed to UV radiation (e.g., a glow-in-the-dark slinky).

Chemiluminescence

Light produced directly by a chemical reaction without a rise in temperature (e.g., a glow stick).

Bioluminescence

Light produced naturally by living organisms (e.g., a firefly).

Triboluminescence

Light produced by friction, such as when wintergreen candy is crushed by a hammer.

Electric Discharge

Light produced when an electric current passes through air or gas (e.g., neon light, lightning).

LED (Light-Emitting Diode)

Light source made of several thin layers of organic molecules that uses electric currents to produce light (e.g., phone backlight).

Crest

The highest point or elevation of a wave.

Trough

The lowest point of a wave below its rest position.

Rest Position

The position of a wave when no wave or disturbance is passing through it.

Amplitude

The height or distance from the rest position to the crest or trough of a wave.

Wavelength

The distance between two consecutive corresponding points on a wave, such as crest to crest.

Gamma Rays

Electromagnetic radiation with the shortest wavelength, used in cancer treatment.

Radio Waves

Electromagnetic radiation with the longest wavelength, used for cellphones.

Infrared Radiation

Electromagnetic radiation commonly used in motion sensors.

X-rays

Electromagnetic radiation that penetrates human tissue but does not pass through bone.

Ultraviolet Radiation

Electromagnetic radiation that can burn skin, increase cancer risk, and excite phosphors to emit light.

Visible Light Spectrum

The portion of the electromagnetic spectrum containing waves between $400\,\text{nm}$ and $700\,\text{nm}$ in length.

Additive Colour Theory

A theory where light is transmitted and primary colours of light (red, green, blue) are added together to produce different colours or white light in hardware like TVs and computer monitors.

Subtractive Colour Theory

A theory where light is absorbed by pigments, using primary subtractive colours (cyan, magenta, yellow) to create colours in printouts and clothing.

Primary Additive Colours

Red, green, and blue light, which combine in equal amounts to form white light.

Secondary Additive Colours

Magenta, yellow, and cyan, which are formed by adding two primary colours of light together.

Primary Subtractive Colours

Cyan, magenta, and yellow pigments, which absorb specific wavelengths of light and reflect others.

Secondary Subtractive Colours

Red, green, and blue, which are formed by combining primary subtractive pigments.

Cyan Pigment

A primary subtractive colour that reflects green and blue light, and absorbs red light.

Magenta Pigment

A primary subtractive colour that reflects red and blue light, and absorbs green light.

Yellow Pigment

A primary subtractive colour that reflects red and green light, and absorbs blue light.

Additive and Subtractive Colour Theory Diagrams

Overlapping circle diagrams illustrating additive colour mixing of light (red, green, blue) and subtractive colour mixing of pigments (cyan, magenta, yellow).