ch 15 Flashcards
what is a period
it is the time between oscillations
what is a traveling wave
it is a organized disturbance that travels through a medium at a well defined wave speed
what is a disturbance
it is a wave caused by a source that passes through a medium at a wave speed (v)
what do waves transfer
they transfer energy but do not transfer materials or substances outward from the source
what is a traverse wave
it is a wave that moves perpendicular to the motion (up and down vs along a line)
what is a longitudinal wave
it is a wave that moves parallel to the motion
what is a wavelength
it is the distance spanned in one cycle of motion
what do soundwaves create
regions of compression and rarefactions
what is a compression
it is regions of high pressure, it appears as a crest on a graph
what is a rarefaction
it is a region of low pressure, it is a trough
what is power of a wave
it is the rate at which a wave transfers energy
describe a circular wave
the power gets spread out from the source and the crests are at the wavefront and are spaced a wavelength distance
what is intensity
it is the brightness or lodness of a wave that depends on the power of the source and the area that receives the power
what
increases loudness of something by a factor of 2?
we have to increase the sound intensity by a factor of 10 in order to see a perceived loudness increase by 2
how much louder is 40 decibels than 20 decibels?
it is 4x as loud
when the source is moving towards the perciever, how is the frequency of the sound perceived
the frequency is higher
when the source is moving away from the perceiver, how is the frequency of sound perceived
the frequency is lower
if a light source is receding from the perceiver, how is the wavelength perceived
it appears longer and is red shifted
if a light source is proceeding toward the perceiver, how is the wavelength perceived
it is shorter and appears blue shifted
what does wave speed depend on?
it depends on the property of the medium, it doesn’t not depend on the shape, size of pulse, how the pulse was generated, or how far it has traveled
