Waves Flashcards
What is a wave?
an oscillation that transfers energy without transferring any matter, by making the particles of the substance (or fields) that it is travelling through oscillate
What does oscillation mean?
vibration
What are the two types of waves?
transverse and longitudinal
What do the words transverse and longitudinal describe?
the direction of the wave oscillations
In the exam, how should you describe the of the wave?
the direction of energy transfer of the wave
In what direction do transverse waves oscillate compared to the direction of energy transfer?
the oscillations are perpendicular to the direction of energy transfer of the wave
In what direction do longitudinal waves oscillate compared to the direction of energy transfer?
the oscillations are parallel to the direction of energy transfer of the wave
What are examples of transverse waves?
light and all other electromagnetic waves, ripples on water, waves on strings or springs when wiggled up and down
What is the area called in a longitudinal wave where the particles are bunched together?
compression
What is the area called in a longitudinal wave where the partcles are spread out?
rarefaction
What are examples of longitudinal waves?
sound waves and a spring when you push the end
In what direction to transverse waves oscillate?
up and down
In what direction do longitudinal waves oscillate?
left to right
What happens to particles when waves travel through a medium?
the particles of the medium oscillate and transfer energy between each other, but overall the particles stay in the same place, only energy is transferred
What are two observations that can be used to explain that waves only transfer energy and not matter?
ripples on a water surface cause floating objects to just bob up and down, they don’t move across the water to the edge, so the wave travels but not the water
if you strum a guitar string and create sound waves, the sound waves don’t carry the air away from the guitar to create a vacuum
What are the waves called that need a medium to travel across?
mechanical waves
What is an example of non-mechanical waves?
electromagnetic waves
What are examples of mechanical waves?
water waves, waves in springs and strings, seismic waves and sound waves
What is the amplitude of a wave?
the maximum displacement of a point on the wave from its undisturbed position (distance from the x-axis to a crest or trough)
What is the wavelength of a wave?
the distance between the same point on two adjacent waves (e.g on a transverse wave it could be the distance between one crest and the next crest)
What is the frequency of a wave?
the number of complete waves passing a certain point per second
What is frequency measured in?
Hertz (Hz)
What is 1 Hz equivalent to?
1 wave per second
What is the period of a wave?
the amount of time it takes for a full cycle of the wave to be completed
(the length of time between one crest passing a point and the next crest passing the same point)
What is the equation for the period of a wave?
Period = 1/frequency
T=1/f
T=period (s)
f=frequency (Hz)
What is the period of a wave measured in?
seconds
What is the wavelength on a longitudinal wave?
the distance between two compressions
What is the equation for wave speed?
(the wave equation)
speed = frequency x wavelength
v=f λ
v=speed (m/s)
f=frequency (Hz)
λ=wavelength (m)
What does the wave equation apply to?
all waves
