ninth paper Flashcards
(33 cards)
what are longitudinal waves? give example
the medium oscillates in the same direction as the wave itself. The particles of the medium are not transported along with the wave.
ex sound waves
what are transverse waves?
the medium is disturbed in a direction perpendicular to the motion of the wave itself. The wave motion is repetetive. The disturbance pattern oscillates continually
what is amplitude?
the distance between the crest of the wave and the maximum displacement of the element from its natural position
define wavelength
minimum distance between any two identical points on adjacent waves
define periods in context to waves
time interval required for two identical points of adjacent waves to pass by a point
define frequency in context to waves
number of crests that pass a given point in a unit time interval.
unit of period =
unit of frequency =
second
hertz
frequency in sound =
frequency in light =
pitch
color
sound is a ____ created by a _____ object in a ____ or ____ medium
wave
vibrating
fluid
solid
we use different terminology for the “peaks” and “valleys” of _____ ______
these terms are compression and expansion
longitudinal waves
define compression
where the medium is squeezed together
define expansion
where the medium is spread apart
what do the vibrations need to be above and below for a human to hear?
more than 20x per second
but no more that 20,000x per second
the wave on a string instrument is longitudinal or transverse? and what for wind instruments?
transverse
longitudinal
speed of sound in
20c air =
iron =
water =
343
5,950
1,493
what are audible waves?
frequencies heard within the sensitivity of the human ear
what are infrasonic waves?
frequencies below the audible range
what are ultrasonic waves?
frequencies above the audible waves
what is the doppler effect?
as the source of sound moves towards the observer the wavelength appears shorter, as the source moves away the wavelength appears longer.
what is a shockwave?
when the speed of the source can exceed the speed of the wave
what are electromagnetic waves?
composed of an oscillating electric field and a magnet field oscillating perpendicular to it.
what is the electromagnetic spectrum?
shows the different types of electromagnetic radiation
what are light waves?
how we perceive different frequencies of light as different colour
what colour do we perceive as a combination of all frequencies?
white
