Chapter 9 Waves, Sound, and Light Flashcards
Explain what a wave is.
A disturbance in space and time that carries energy from one place to another.
Define frequency.
the number of cycles completed per second. (units Hz)
Define period.
the length of time required to complete one cycle. (units s)
define wavelength
the distance between the peaks of a wave.
Define amplitude.
the height of a wave, measured from the centerline of a wave to the top of a peak (crest).
Name the five wave interactions.
Reflection
Refraction
Diffraction
Resonance
Interference
Describe reflection
When a wave bounces off a reflecting surface, obeying the the law of reflection in the processs.
Describe refraction
When a wave passes through the boundary separating two media, change velocity and direction in the process.
Describe Diffraction.
When waves encounter corners of obstruction, bending or speading out as a result.
Describe Resonance.
A wave interaction produced when the dimensions of a medium correspond to a multiple of half the wavelength, resulting in standing waves and higher amplitudes.
Describe interference.
A wave interaction produced when two waves arrive ate the same place and time. If the wave arrive in phase (constructive interference), wave amplitudes add together. If out of phase (destructive interference), the waves cancel out.
Describe longitudinal waves.
The oscillation moving a in a direction paralell to the direction which the wave is propagating. Example: Sound waves in air.
Describe Transverse waves.
A wave produced by an oscillation moving in a direction perpindicular to the direction of wave propagation.
Example: light and other electromagnetic waves
Describe Circular waves
the movement of the medium is in a circle.
example: waves on water formed by the wind.
Define infrasonic.
A sound with a frequency below 20 Hz, the lower limit of human hearing.
