Physics chapter 12 Flashcards
Define stringed instruments?
A musical instrument having strings as the medium of sound production
Examples of string instruments?
Guitar, Harp, Violin
Define wind instruments?
A musical instrument in which sound is produced by the vibrating of air, typically by the player blowing into the instrument.
Examples of wind instrument?
Flute, Clarinet, saxophone, French horn
Define percussion instruments?
Any instrument that makes a sound when it is hit, shaken or scraped. Some percussion instruments are tuned and can sound different notes..
Examples of percussin instruments?
Piano, Drums, Maracas, xylophone
Define sound?
A form of energy produced and transmitted by the vibrating matter travels in waves and travels more quickly through solids compared to liquid or gasses.
How does sound reach our ears?
Sound is carried to our ears through the vibrating of air molecules.
Function of ear?
They take in sound waves and convert them to signals for our brain.
Name the 3 parts of the ear that sound moves in?
Outer ear, Middle ear and Inner ear
Define vibration?
Back and forth movement of molecules of matter
Why can’t sound travelk through a vacuum?
Sound needs a medium in order to be transferred such as solids, liquids or gasses. Due to this sound can not travel in a vacuum.
What is the speed of sound?
330m/s or 1200km/h
Define frequency?
Number of waves per second passing a point
Define wavelength?
The distance between two adjacent crests or troughs of a wave.
What is the equation for frequency?
Velocity / Wavelength
Do different materials transmit sound faster?
Yes
Why do different instruments produce different sounds?
Becasue they have differant shapes
How does a microphone work?
It recieves the vibrations and converts them to electrical signal.
Define period?
Number of seconds for one vibration
Formula for period?
T (period) = 1/f (frequency)
Define frequency?
Number of vibrations per second
Define wavelength?
Length of the wave from one peak to the next.
What is pitch?
A meassure of how high or low a sound is
What does pitch depend on?
It depends on frequency of a sound wave
How can instruments be played at different pitches?
It can be done by changing the lengths of different parts.
What is Infrasound?
Sounds below 20Hz
What is Ultrasound?
Sounds above 20,000 Hz
What is the range of hearing?
20 Hz to 20,000 Hz
On what surface is sound reflected better?
Sound reflects better on a rigid and smoother surface
On what surface is sound reflection bad?
Sound reflection is bad on a soft and irregular surface.
What happens when more sound energy is reflected?
The sound becomes louder
What does the reflection of sound depend on?
The nature of the surface
What is Noise?
Unpleasent sound is called noise
What can result from over-exposure to noise?
It can result in headaches, sleep deprivation and stress.
What is it called when pressure of sound increases?
Compression
What is it called when the pressure of sound is decreased?
Rarefraction
Define compression?
The part of sound wave where molecules are crowded together.
Define rarefraction?
The part of the sound wave where molecules are spread apart
Define the vibrations in a longitudinal wave?
The vibrations are parallel to the direction of wave travel.
Examples of longitudinal waves?
Sound waves, Ultra sounds
Define the vibration is transverse waves?
The vibrations are at a right angles to the direction of the wave travel.
Examples of transverse wave?
. Ripples on the surface of water
. Vibrations in a guitar string
. A mexican wave in a sports fesstival
. Electromagnetic waves (Light waves, Microwaves, Radio waves)
Properties of longitudinal sound waves?
- They consist of compressions and rarefractions
- There is a pressure variation throughout the medium
- They can be propogated through solids, liquids and gasses
- There is a change in the density throughout the medium
- The particles vibrate parallel to the direction of wave travel
Properties of Transverse waves?
- It consists of crests and Troughs
- There are no pressure variations
- They can be propegated through solids and liquids but not gasses
- The particles of the medium vibrate at right angles to the direction of wave travel.
- There is no change in the density of medium.
Explain in term of compresions what wavelength is?
Wavelength is the distance from one compression to the other
What is the speed of light
3*10⁸
Speed of sound in water
1500m/s