Unit 5 Lesson 1 : waves and light Flashcards
Medium
The material through which a wave travels.
Wave
A disturbance that transfers energy from one place to another.
Longitudinal wave
In a longitudinal wave particles move back and forth in the same direction that the wave travels, or parallel to the wave.
Transverse wave
In a transverse wave, particles move perpendicularly to the direction the wave travels.
Mechanical wave
Waves that require a medium.
Electromagnetic waves
Are disturbances in electric and magnetic fields.
Amplitude
A measure of how far particles in the medium move away from their normal rest position.
Wavelength
Is the distance over which the waves shape repeats.
Wave period
Is the time required for one cycle.
Frequency
Tells you how many cycles occur in an amount of time, most commonly 1 s.
Hertz
One hertz is equal to one cycle per second.
Wavefronts
The peaks can be drawn as shapes, such as circles or spheres, called wavefronts.
Wave speed
The speed at which a wave travels.
Radiation
Is the transfer of energy as EM waves.
Electromagnetic (EM) spectrum
However, visible light represents only a very small frequency (or wavelengths) that an EM wave can have.
Infrared or IR
Infrared or IR, light has slightly longer wavelengths than red light.
Ultraviolet, or UV
Ultraviolet or UV, light has slightly shorter wavelengths than violet light.
Transparent
Matter that transmits light.
Translucent
Materials transmit light but do not let the light travel straight through.
Opaque
Opaque materials do not let any light pass through them.
Absorption
Is the transfer of light energy to matter.
Reflection
The bouncing of light off a surface.
Refraction
The change in direction of a wave as it passes from one medium into another at an angle.
Scattering
Occurs when light is sent in many directions as it passes through a medium.
