Electromagnetic Waves (18.1)

Transverse waves

Waves in which the magnetic and electric fields are at right angles to the direction of the wave.

Electromagnetic radiation

The transfer of energy by electromagnetic waves.

Medium

Substance through which waves can travel.

Speed of light

The speed at which electromagnetic waves travel in a vacuum, which is 3.00 x 10^8 meters per second.

Frequency

The number of complete waves that pass a given point in a certain amount of time.

Wavelength

The distance between two corresponding points on a wave.

Inversely proportional

When two quantities change in opposite directions.

Wave-particle duality

The concept that electromagnetic radiation can behave both as a wave and a stream of particles.

Constructive interference

When two waves combine to create a larger amplitude.

Destructive interference

When two waves combine to create a smaller or zero amplitude.

Photoelectric effect

The emission of electrons from a material when exposed to light.

Photons

Packets of electromagnetic energy.

Intensity

The rate at which a wave's energy flows through an area.

Concentration

The degree of how closely packed the photons are.

Spread out

The dispersion of photons as they travel further away from the source.

Decreases

The reduction in intensity as photons travel further away.

Flashlight beam

An example of a source of electromagnetic waves.