Physics Ch 11&12
Distinguish between constructive interference and destructive interference.
Constructive interference increases the amplitude of a wave, while destructive interference decreases the amplitude of a wave.
Why is loudness subjective and intensity is not?
Intensity is the actual measurement of the amplitude of the wave, whereas loudness is a physiological perception.
If you triple the frequency of a vibrating object, what will happen to its period?
It will be 1/3 of the original size
Would it be correct to say that the Doppler effect is the apparent change in the speed of a wave due to motion of the source?
NO The Doppler Effect is the apparent change in the FREQUENCY of a wave, it does not change the speed of the wave.
3. Does the medium in which a wave travels move along with the wave itself? Defend your answer.
No, the medium transmits the wave but does not travel itself (see question #1 on the conceptual challenge)
Does the medium travel with a sound wave? Why
No, the particles vibrate in order to transmit the wave but they do not actually move with the wave itself
Can a sound wave travel through a vacuum? Why?
No, there has to be a medium (particles) in order to transmit a sound wave.
the _______ is the height of the wave
amplitude
What is the area of a sound wave where the pressure is higher?
compression
what is the area of a sound wave where the pressure is higher?
compression
where the crest of the waves match or overlap & the amplitude is increased
constructive interference
occurs when an object is made to vibrate by another object that is vibrating nearby
forced vibration
the number of vibrations or complete back and forth motions per unit of time
frequency
what happens to the wavelength if the frequency of pulses is increased?
frequency increases and wavelength decreases
if you double the frequency of the sound wave, determine its speed.
if you double the frequency of the sound wave, determine its speed.
sound waves with frequencies below 20Hz
infrasonic
what is the relationship between wavelength and frequency
inversely proportional λ= v/f
fwhat is the relationship between period and frequency
inversely proportional; T = 1/f
where are your auditory sensor cells found?
organ of corti
Does the Doppler effect occur for only some types of wves or all types of waves?
All Waves
How fast does sound travel?
340m/s
How fast does light travel?
3x108m/s
when will hearing damage occur?
85dB
Why do you see lightning before you hear thunder?
Because light travels almost 1 million times faster than sound.
Sound travels as what type of wave?
Longitudinal
Distinguish between the period and the frequency of a vibration or a wave. How do they relate to one another?
The period is the time it takes to complete one cycle (wave) whereas the frequency is how many cycles (waves) are created per second.
When a wave source moves toward a receiver, does the receiver encounter an increase in wave freuency, wave speed, or both?
The receiver will encounter and increase in wave frequency only! The speed of the wave only changes if the medium changes.
As the frequency of sound is increased, does the wavelength increase or decrease? Give an example.
The wavelength decreases.
Astronomers find that light coming from point A at the edge of the sun has a slightly higher frequency than light from point B at the opposite edge. What do these measrements tell us about the sun's motion?
This means that point A is moving toward earth and point B is moving away from earth.
The highest point on a wave is _____, The lowest point on a wave is ________
crest; trough
where the crest of one wave overlaps the trough of another and the amplitude is decreased
destructive interference
what is the relationship between wavelength and period
directly proportional λ=VT
wave that moves back and forth in same direction as the wave
longitudinal wave
the place on the wavelength where there is now movement
node
the time it takes to complete on back and forth vibration
period
What is the area of a sound wave where the pressure is lower?
rarefaction
what is the area of a sound wave where the pressure is lower?
rarefaction
wave that creates a right angle
trnsverse wave
sound waves with frequencies above 20,000Hz
ultrasonic
waves carry ______ from one place to another
vibrations
Red light has a longer wavelength than violet light. hich has the greater frequency?
violet
the distance from one crest to the next is ________
wavelength
what happens to wavelength if you cut the frequency in half
wavelength doubles because they're inversely proportional