Chapter 6-7: Electromagnetic Waves and Light (Video Notes)

Vocabulary flashcards covering key terms and concepts from electromagnetic waves and light presented in the video notes.

Electromagnetic wave

A wave made of changing electric and magnetic fields that travels and carries energy.

Speed of EM waves

All electromagnetic waves travel at about 300,000 kilometers per second (the speed of light in vacuum).

Wave

A disturbance that transfers energy from one place to another.

Particle

A piece of matter; often contrasted with a wave in wave–particle discussions.

Photon

A massless bundle of energy that behaves like a particle.

Radio waves

Electromagnetic waves with wavelengths longer than 10 cm.

Audio transmission

Radio waves carrying sound signals; the radio converts these waves into audible sound.

Radar

A system that uses radio waves to detect the position and movement of objects.

Microwaves

Electromagnetic waves with wavelengths between 0.1 mm and 30 cm.

Infrared waves

Electromagnetic waves with wavelengths about 700 billionths of a meter.

Visible light

The range of electromagnetic waves detectable by the human eye.

Ultraviolet waves

Electromagnetic waves with wavelengths from about 400 billionths of a meter (400 nm) to shorter wavelengths.

Gamma rays

Electromagnetic waves with wavelengths shorter than about 100 trillionths of a meters.

Carrier wave

An electromagnetic wave with the specific frequency assigned to a station.

Modulation

The process of adding the information signal to the carrier wave.

GPS (Global Positioning System)

A system of satellites, ground stations, and receivers that determines your exact location on or above Earth.

Opaque

Materials that absorb and reflect light; light does not pass through.

Translucent

Materials that transmit light but scatter it; objects appear blurry.

Transparent

Materials that transmit light without scattering; you can see clearly through them.

Reflection

Light waves bounce off a surface.

Law of reflection

Angle of incidence equals angle of reflection.

Diffuse reflection

Reflection from rough surfaces that does not form a clear image.

Regular reflection

Reflection from smooth surfaces that does form a clear image.

Refraction

Change in direction of light as it passes from one material to another due to a change in speed.

Index of refraction

A property of a material indicating how much light slows in that material compared with vacuum.

Prisms

Refract white light and separate it into a spectrum of colors.

Mirages

Images of distant objects formed by refraction of light through air layers of different densities.

Interpreting color

Color perception arises from mixing signals from cone cells in the eye.

Filter

A transparent material that transmits only certain wavelengths of light.

Paint pigment

A colored material used to change the color of other substances.

Incandescent

Light generated by heating a material (usually a metal) until it glows.

Fluorescent

Light generated by phosphors converting ultraviolet radiation to visible light.

Neon lights

Electricity excites gas in tubes, producing glowing colors.

Tungsten-halogen lights

Brighter and longer-lasting bulbs often used for intense lighting.

Lasers

Concentrated light of a single wavelength; used in surgery, shows, and technology.

Coherent light

Light with a single wavelength where crests are in step and travel in one direction with fixed spacing.

Incoherent light

Light with multiple wavelengths, traveling in many directions and with no fixed crest spacing.

CDs and video discs

Plastic discs with reflective surfaces that store sound, images, and text in digital form.

Polarized light

Light in which the electric (and magnetic) field oscillates in a single plane.

Holography

A technique that records and reproduces a hologram (3D image).

Optical fibers

Flexible strands of glass or plastic that transmit light to carry information.

Partial reflection

At a boundary between two media, part of the light is reflected back and part is transmitted.