Waves - Properties Of Waves Flashcards
What is a wave
An oscillation that transfers energy without transferring matter
What are transverse waves
Oscillations are perpendicular to the direction of energy transfer
What type of waves are transverse waves
Ripples on water
Waves on strings and spings
Light and all other electromagnetic waves
What are longitudinal waves
Oscillations parcel to direction of energy transfer
They have areas of pressure and rare rarefraction
Name examples of logitudal waves
Sound waves and a spring when you push the end
What is the amplitude
Maximum displacement from the rest point
What is wave lenghth
The distance between the same point on 2 adjacent waves
What is frequency
The nummber of complete waves passing a point per second
Measured in Hertz Hz
What is the time period
The amount of time it takes for a complete cycle of one wave
What is the equation that includes time period
1/frequency
What is the equation for wave speed
Speed(m/s) =frequency x wavelength (m)
how do u measure the speed of sound
play a speaker with a set frequency (use a signal generator)
get 2 microphones attached to an oscilloscope
slowly move one microphone away from the speaker until the waves alliin again. this is when they are one wavelength apart.
measure the distance between them
find the speed by doing frequency x wavelength
what is the speed of sound in the air
330m/s
what is a boundary
between 2 different materials
what 3 things can happen to a wave at a boundary
absorption, reflection, transmission
what is a ray
a straight line showing the path of a wave
what is a normal
a straight line that is 90 degrees to the boundary
what is the angle between the ray and the normal called
angle of incidence
what is the angle between the normal and the refracted ray called
angle of refraction
why does refraction occur
waves travel faster in some materials than others. when a wave refracts it changes speed, not frequency
what are wavefronts
imaginary lines drawn through certain points on waves at right angles to the waves
what are wavefronts useful for
explaining why waves refract across boundaries
why does a wave change direction when it refracts
because its at an angle to the boundary, one end changes speed before the rest of the wave causing it to change direction
where will a wave bend if it slows down at a boundary
towards the normal
where will a wave bend if it speeds up at the boundary
away from the normal
what is the correlation between the angle of incidence and the angle of reflection when a wave is reflected
angle of incidence = angle of reflection
what is specular reflection
parallel waves reflected in a single direction by a smooth surface. e.g. when light is reflected by a mirror
what is diffuse reflection
parallel waves reflected by a rough surface so reflected waves are scattered in lot of different directions. this is because the normal varies on rough surfaces
