Waves - Sp4 Flashcards
what angle are the vibrations to a transverse wave
90 degrees - perpendicular
What types of transverse waves are there
electromagnetic, S-waves, waves in water
(MOST WAVES ARE TRANSVERSE)
Using a spring as an analogy, how are transverse waves created
The spring moves up and down to create the pattern more commonly seen
At which angle do vibrations within longitudinal waves occur?
they travel along the same plane as the wave at the same angle (parallel)
What types of waves are longitudinal?
P-waves and sound waves
What do you call the compressed parts of longitudinal waves
compressions
what do you call the extended parts within longitudinal waves
rarefractions
which 2 equations calculate wave speed?
Frequency x wavelength
or
distance/time
what are the purposes of waves?
to transfer energy + information (not matter) in direction they are travelling
How do waves work?
The particles in a medium vibrate to transfer energy between eachother
what is the definition of frequency
number of complete cycles of the wave passing through the same point (eg crest to crest) per second
how is frequency measured?
in Hz (1Hz = 1 wave a second)
What is a period?
number of seconds taken for a full cycle of the wave to occur
what is the difference between transverse and longitudinal waves?
transverse = perpendicular (all electromagnetic + s waves)
longitudinal waves = parallel (sound + p waves)
how does one measure velocity of sound in air?
speed = frequency x wavelength
how does one measure velocity of sound on the surface of the water?
speed = frequency x wave length
How does the direction of a wave change through different materials? and why does it? when does the direction not change?
due to different densities, the speed changes when a wave crosses a boundary meaning change in speed can cause a change in direction (if it hits it at an angle (this is refraction)) - if travelling along the normal the direction does not change.
What happens to the direction of a wave when the change in speed is greater
the wave will bend more
what is the effect of a wave being reflected?
reflected light is scattered in all directions, creating distorted images
what are the effects of waves being refracted
change direction and speed
effects of waves being absorbed and transmitted?
energy is transferred to the particles in the object - causing vibrations
Describe how changes in velocity, frequency and wavelength are related when sound waves go from one medium to another
the velocity is directly proportional to the wavelength - any change in wave length is changed in velocity (e.g when the wave gets longer, the velocity increases). frequency doesn’t change.
list the parts of the human ear in order of how they transmit vibrations
soundwaves reach ear drums - cause them to vibrate
passes on to ossicles
then through semi-circular to the cochlea
turned vibrations into electrical signals sent to your brain
what is the function of the ear drum
to create vibrations
function of the cochlea
turn vibrations into electrical signals
how are sound waves in air converted into vibrations in solids
as the wave travels through air, it compresses and refracts - upon hitting a solid object, the air particles hitting cause the particles in the solid to move back and forth - these then hit the particles next in line and so on
what factors effect how well sound waves transfer energy to solids
distance to object, speed of wave, the amount of particles to move in the area
why can the human ear only detect a range of freqencies
due to shape and size - as it is small, the ear can only transfer a certain amount of energy without being hurt
