4 Properties of Waves Flashcards
Waves transfer ______ without transferring ______
energy, matter
Describe wave motion
Illustrated by vibration in ropes and springs, and experiments using water waves
Understand the term wavefront
wavefronts are imaginary surfaces through crests, perpendicular to the direction of energy propagation of the wave
Understand the term ray
The ray is a mathematical line perpendicular to the wavefront, giving the direction of energy transfer of the wave
State the meaning of the speed of a wave
how fast the wave is traveling
State the meaning of the frequency of a wave
the number of peaks or troughs that pass a certain point each second, or the number of cycles completed in a second
State the meaning of the wavelength of a wave
the distance between two consecutive compressions or rarefactions
the distance between two successive crests or troughs
State the meaning of the amplitude of a wave
the difference between a crest or a trough and the equilibrium
State the meaning of a node in a wave
where the wave crosses the equilibrium
State the meaning of the equilibrium of a wave
the midline of the wave, the medium of the wave’s resting position
State the meaning of the crest of a wave
the highest point on a wave
State the meaning of the trough of a wave
the lowest point on a wave
State the meaning of the trough of a wave
the lowest point on a wave
Define a wave
an oscillation or vibration accompanied by a transfer of energy that travels through space or mass
Define a medium
an intervening substance through which a wave can transfer its energy
Transverse wave
a wave vibrating perpendicular to the direction of travel in a sine curve shape
Longitudinal wave
a wave vibrating in the same direction it is traveling
State the meaning of a compression of a wave
a region in a longitudinal wave where the particles are closest together
State the meaning of a rarefaction of a wave
a region in a longitudinal wave where the particles are furthest apart
Examples of transverse waves
light, water
Example of longitudinal waves
sound
Example of longitudinal waves
sound
Characteristics of electromagnetic and mechanical waves
electromagnetic - oscillating electric/magnetic fields
mechanical - oscillating particles
Units for frequency of a wave
Hertz (Hz)
1Hz = 1/s
Equation relating wavelength, frequency and speed of a wave
v = fλ
speed of wave = frequency x wavelength
m/s = Hz x m
The denser the medium, the ______ the mechanical wave travels and the ______ the electromagnetic wave travels
faster, slower
Pitch
High: waves close together / high frequency
Low: waves further apart / lower frequency
Pitch
High: waves close together / high frequency
Low: waves further apart / lower frequency
Loud sounds =
Quiet sounds =
high amplitude
low amplitude
Humans can detect frequencies between …
20Hz and 20,000Hz
Diffraction
when waves travel through a narrow gap of width approximately equal to their wavelength, the waves diffract - diffracting waves widen after travelling through the gap
Echo formula
speed = distance / time
where distance = x2
No sound in vacuum because …
No particles to transfer the energy
An electromagnetic field is the ___________ of an ___________ electric field
propagation, oscillating
Electromagnetic waves are all __________ waves
transverse
Electromagnetic spectrum order
radio waves, microwaves, infra-red, visible light, ultraviolet, x-rays, gamma rays
Electromagnetic spectrum order: does frequency increase or decrease along it?
increases
Electromagnetic spectrum order: does wavelength increase or decrease along it?
decreases
For light, wavelength and frequency are …
inversely related
Properties of reflected images (6)
right way up, same size, same colour, virtual, same distance, laterally centred
Formula for refractive index
n = sin(i) / sin(r)
Speed of electromagnetic waves in a vacuum
3 x 10⁸ m/s
