Sound Flashcards
definition of sound
Mechanical waves produced by a vibrating object, e.g. tuning fork.
fundamental frequency
The frequency at which a body tends to vibrate if free to do so.
harmonics
Frequencies that are multiples of the fundamental frequency. If f = fundamental frequency, then f = 1st harmonic.
the fundamental frequency of a string is the lowest frequency that can be produced by the spring.
overtones
Frequencies that are multiples of the fundamental frequency. If f = fundamental frequency, then 2f = 1st overtone.
resonance
resonance is the transfer of energy so that a body vibrates at its natural frequency E.G. microwaves
sound intensity
The power carried by sound waves per unit area in a direction perpendicular to that area.
sound intensity levels
Measured in decibels, it gives the intensity of a sound relative to the threshold of hearing.
Natural frequency
the frequency at which an object will vibrate if free to do so
What type of wave is sound
Longitudinal/Mechanical
what evidence is there that sound diffracts?
it travels around corners
Can sound waves be polarised?
No, as they are longitudinal waves
Node definition
a point on the standing wave when there is no vibration
antinode definition
a point on the standing wave where there is a maximum vibration
what is the wavelength of a standing wave?
the distance between every second node.
Standing wave definition
when two waves of the same frequency and amplitude moving in the opposite direction interfere with each other.
This only occurs when one wave is out of phase by half a wavelength with the other
Wave equation
c=f lambda
c is speed of light
f is frequency
lambda is the wavelength.
forces that determine the frequency of a stretched string
length
tension
mass per unit length
what do air columns open at Both ends produce
harmonics that are both odd and even multiples of the fundamental
doppler effect
uses of the doppler effect
the apparent change in frequency of a node produced if there is relative movement between the source and the observer
Speed trap gun used by gardaí
what do air columns open at one end produce
odd multiples of harmonics of the fundamental
hooke’s Law
States that when an object is bent,stretched or compressed by displacement ‘s’, the restoring force ‘F’ is directly proportional to the displacement - providing the elastic limit is not exceeded. (F=-ks)
