p6 Flashcards
What are the two types of waves
-longitudinal
-transverse
What do all waves do
All waves transfer energy from one place to another
What are ocillations
The movement of waves up and down
What are the oscillations like in transverse waves
Occultations are perpendicular to the direction of energy transfer
What are the oscillations like in longitudinal waves
Oscillations are parallel to direction of energy transfer
What do all longitudinal waves require
A medium to travel in eg liquid or solid
What is amplitude
The maximum displacement of a point on a wave away from its undisturbed positions
What is a wavelength
The distance from a point on one wave to the equivalent point on the adjacent wave
What is frequency of waves
-number of waves passing a point per second
-hertz (Hz)
-1 Hertz=1 wave per second
What is the period of a wave
The time(in seconds) for one wave to past a point
What is the equation for period
1/frequency(Hz)
What is wave speed
The wave speed is the speed which the wave moved through the medium (the speed at which energy is transferred)
What is the equation for wave speed
Frequency(Hz) x Wavelength(m)
What method can we use to Measure speed of sound waves in air
Two people 50m apart,person a had symbols,person b has timer,person b darts the timer when they see symbols clashing,stops when they hear it,use distance travelled/time taken
What are the problems with method to measure wave speed
-every person has differnt reaction time
-reduce error by having a large number of observers with timer and find mean
What are electromagnet wanes
Transverse waves that transfer energy from the source to absorber
What are the properties of waves on the left(red) side of the electromagnetic spectrum
-low frequency
-low wavelength
What are the properties of waves on the right side of the electromagnetic spectrum
-high frequency
-short wavelength
What does
Rich,Men,In,Vegas,Use,eXpensive,Gadgets
Show
Radio,microwaves,infrared,visible,ultraviolet,x-Rays,gamma
Why can electromagnetic waves travel through a vacuum
They do not need a medium to travel through
What speed do waves travel through in a wave
3x10(8) m/s
(300,000,000)
What is refraction
Waves can change direction when they change speed moving one medium to another
What happens if waves enter or leave the medium at right angles
They do not change direction
What is a wavefront
An imaginary line that connects all the same points in a set of waves
What happens when light waves move from air to glass
-first part of the wavefront slows when it moves into glass
-those parts of the wavelength get closer
-wavelength gets smaller and change direction to the normal
What happens to wave direction when they sped up
Change direction way from the normal
What happens when EM waves are absorbed or generated
Changes take place in atoms or nuclei of atoms
What happens to the nucleus of gamma rays are emitted
The nucleus has less energy then it had at the start
How can radio waves be produced
-radio waves can be produced when electrons oscillate in electrical currents
What are the used of radio waves
-transmit radio
-terrestrial TV signals
What are the uses of micro waves
-heat food
-communicate with satellites
What are the use of infrared waves
-Heat food
-infrared cameras
What are the uses of visible light
-communication in fibre optics
Uses of ultra violet
-energy efficient lightbulb
-sun tanning
Uses of x-rays and gamma rays
-medical treatment
-medical imaging
-detect cancers
Describe how the radio waves reaching the car aerial produce signals in the electrical circuit of the car radio.
-(the car aerial) absorbs radio waves or energy
-electrons are made to vibrate (in the aerial)
-creating an alternating current (in the aerial circuit)
-the (signal) frequency is the same (as the radio wave)
Explain why the light refracts as it passes from air into glass
-speed / velocity in the glass is lower
-so the edge of the wave(front)entering the glass slows down
-but the part of the wave(front) in
the air continues at the higher
speed / velocity
