Sound Flashcards
Def a longitudinal wave
Is a disturbance - the displacement of which is in the direction of propagation
Define a wavelength
Is the distance between 2 corresponding points on two successive waves
Define frequency
It is the number of waves passing a given point in one second
Define Amplitude
It is the maximum displacement attained from the undisturbed position
What is the formula for the speed of sound
V=d/t
v = velocity in m/s d = distance travelled in m t = time in s
Also v = lambda x f
Describe an experiment to determinethe speed of sound
Tapemeasure
Stopwatch
Starters pistol
500m open field
3 pupils with stopwatches on one side
Another pupil 500m away firing the pistol
Stopwatches started when smokeis seen and stopped when sound is heard
Average of 3 times calculated
Use formula to calculate v=d/t
Name 4 facts about sound
Travels faster at higher temperatures
Travels faster and better in liquids than air
Solids transmit sound best, fastet, and furthest
Greter speed in liquid and solids due to greater elasticity
Define an echo
It is a repetition/s of sound caused by the reflection of soundwaves from a hard surface such as a wall or cliff
Name 3 conditions necessary to form an echo
Loud enough sound
Large enough reflective surface (rock / wall)
Far enough from reflective surface (17m)
Name 3 characteristics of sound
Pitch
Loudness
Quality
What attribute of a wave cause the pitch of sound
Frequency
Name 3 factors that determine the pitch of a piano string
Length
Thickness
Tension
What attribute of a wave cause loudness
Amplitude
What cause the quality of a note
Faint overtones formed along with the fundamental note
What is meant by the quality of a note
It determines the difference in sound between a note played on a piano and the same note played on a violin
What are the limits that the human ear is capable of hearing
20Hz - 20000Hz
At what frequency do we describe ultrasound
20 000Hz and higher
Give 4 uses of ultrasound
Image the human body -diagnostic tool
Industrially to find flaws in material and measure thickness of objects
As a non invasive sensor to detect the content of containers
To break up kidney stones without surgery
Difference between a misical note and noise
Noise is caused by irregular vibration while a musical note is caused by a regular vibration
Def electromagnetic waves
Are progressive transverse waves that are made up of alternating electric and magnetic fields that are at right angles to each other
In what respect are all electromagnetic waves the same
They all travel at the same speed. 3 x 10 ^8m/s
Electromagnetic waves differ from each other in respect to ……… And …….
Frequency
Wavelength
Give 6 properties of EM waves
Can travel through a vacuum
Are transverse waves
Travel at a speed of 3 x 10^8 m/s in a vacuum
Exhibit reflection, refraction, diffeaction, interference and polarization
Transmit energy from one place to another
Can be absorbed by matter to cause heating and other effects
How are radio waves produced?
By oscillating currents in an aerial
A radio receiver does not need to be in line of sight from the transmitter to receive the signal - explain
Radiowaves can be diffracted or reflected around obstacles
Long wave transmission is ised in mountainous areas because long waves are diffracted better over the mountain tops - so that transmissions can be received in the valleys.
They are also reflected by charged particles in the ionosphere which makes long distance world service radio reception possible aroun the curvature of the earth
Microwaves are at the Short /Long wavelength end of the radio band
Short
Microwaves are used for
Cooking in microwave ovens
For communication by cell phone and with satellites
Infrared radiation is characterized by
Heat
Infrared can be detected by
Skin
Thermometer
Temperature sensitive photographic film
What is infrared radiation used for
Trigger burglar alarms
In remote controlls for TVs
In heaters toastera and grills
To transmit communication signals in optical fibre cables
White light can be split in all the component colours / spectrum of light
Name the colours in decending wavelength
Red Orange Yellow Green Blue Indigo Violet
Def monochromatic light
Light of one colour and therefore of one frequency
Ultraviolet rays causes
Sunburn
Name uses for ultraviolet radiation
Sunbed
Security pens
Fluorescent lights
Killing virusses and bacteria
How are x rays produced
In an x ray tube when high velocity electrons strike a metal target
How are gamma rays produced
Radioactive decay of unstable atoms
How can we detect gamma rays
Geiger counter
What is gamma radiation used for
Sterilize surgical instruments
To kill harmful bacteria in food
To kill cancer cells
List electromagnetic waves from longest to shortest wavelength
Radio waves
Micro waves
Infra red waves
Visible waves
Ultraviolet
X rays
Gamma rays
Def sound waves
Are longitudinal waves that are Made up of a series of compressions and rarefactions caused by vibrations
