sound intensity - Answers - how often something vibrates
- it is also important to know something about the strength or extent of the vibration or displacement
- this refers to intensity or pressure
what is energy? - Answers energy is the ability to do work
how is engird measured? - Answers joules
what is power? - Answers power is the rate at which work is done
what is power measured in? - Answers watts
what is the formula for power? - Answers power= energy/time
what is intensity? - Answers intensity is the amount of energy transmitted per second over a given area
what is force? - Answers - force represents the interaction of an object with its environment
-applies force may result in change in an object's position/ velocity/ acceleration
what is the formula for force? - Answers force= mass x acceleration
how is force expressed? - Answers - the dyne (a force capable of accelerating a mass of 1 gram to a
velocity of 1 centimeter per second square)
- for comparison, 1 gram (1/30 oz.), at sea level, exerts a force of about 1000 dyne
what is newton? - Answers - the newton has also been used as a unit of force
- one Newton (N) is capable of accelerating a mass of 1 kilogram to meter/s
- one Pascal (Pa) is a unit of pressure equal to 1N/ square meter
what is pressure? - Answers - pressure is generated when force is distributed over a surface area
(pressure= force/area)
- normal atmospheric pressure is about 14.7 pounds/ square inch)
- this pressure is equivalent to 1 million dyne/ square centimeter
what is the formula for pressure? - Answers pressure= force/ area
what is the smallest pressure that a person with normal hearing can just detect is ______ dyne/ square
centimeter - Answers .0002
, pressure and hearing - Answers - the smallest pressure that a person with normal hearing can just
detect is 0.0002 dyne/ square centimeter (our reference point)
- this literally means that the force is 0.0002 dyne and the area is one square centimeter
- 20 microPascals (uPa) is equivalent to 0.0002 dyne/ square centimeter
what is intensity? - Answers intensity is the amount of sound energy transmitted per second per unit
area
intensity and pressure - Answers intensity level (IL) is the power of a sound per unit area
these intensity and pressure, are the 2 ways quantifying sound level
pressure is= _______/_______ - Answers pressure is force/area
decibels - Answers the decibel is a method for expressing a ratio between numbers which:
- involves a ratio
- involves a logarithm
- is expressed in terms of its reference which must always be specified
- is NOT a unit of measure
huge dynamic range of hearing necessitates a scale of numbers besides a linear one-- so, use logarithms
or exponents so we can have a number scale going from about 0 to 1000-- that's why we're going to use
decibels to measure sound intensity or sound pressure
Decibels is expressed as its - Answers reference which must always be specified
what is a logarithm? - Answers logarithm is numeric shorthand. a sateen if numeration where one
number 'stand' for another number
why are logarithms useful? - Answers logarithms are useful when reducing large numbers to smaller
manageable numbers
the log of 1 is... - Answers 0
the log of 10 is... - Answers 1
the log of 100 is... - Answers 2
what is intensity? - Answers - the amount of sound energy per m^2 or cm^2= Intensity