4 waves Flashcards
longitudinal
parallel to the direction of travel
can’t be polarised
Sound waves
waves
mechanical
-passes through solid materials by vibrating the particle in the substance
electromagnetic
- waves can pass through a vacuum
- electric field and magnetic field are at 90 degrees to each other
transverse wave
perpendicular to direction of travel
Can be polarised so is a best for transverse waves
Electromagnetic waves and waves on a spring
polarisation
transverse waves are polarised if they all travel in the same plane
(lights isn’t bright)
displacement
vibrating particles distance from its equilibrium point
amplitude
maximum displacement
wavelength
distance from two nodes
cycle
max displacement to the next max displacement
period
time from one complete wave
frequency
F
phase difference
1 cycle = 360
a different place in the wave cycle
reflection
i=r
refraction
bends towards the normal when a light ray enters a denser substance
diffraction
narrower gap the waves spread out more
(dish desgin
-bigger dish = stronger signs)
(stationary and progressive wave)
frequency
s- all particles except at the same frequency
p- all particles vibrate at the same frequency
(stationary and progressive wave)
Amplitude
s- zero to the maximum
p- same aplitude
(stationary and progressive wave)
Phase difference
s- mπ
p- 2πd
————
λ
harmonic tones
example = stationary wave
-sound in a pipe
resonates at certain frequencies
antinode= bottom end
node = other end
-microwaves
fundamental wave
λ= 2L (2 nodes)
λ= L (3 nodes)
λ=2/3L (4 nodes)
fundamental wave frequency
only happens at wavelengths of a whole number
F1 = C/2L
F2=C/L
F3=3C/2L
F4=2C/L
Oscilloscope
specially made electron tube and control curcuits
displacement of the spot is proportional to the applied pd
Oscilloscope
peak pd?
amplitude * y-gain
Oscilloscope
Time
time base * one wave distance
Speed
Distance divided by time
Phase
Defined as the distance between first zero-crossing and the point in space defined as the orgin
Phase difference
Difference between two waves having the same frequency and reference to the same point in time
True of false
All electromagnetic waves travel at the same speed in a vacuum
True
Stationary wave
Standing wave
Combination of two waves moving in opposite directions, each having the same amplitude and frequency, which results in interference and then the waves are superimposed or destructive
Node
Part of the wave that stays still
Path difference
Difference in meters between the length of two paths
Coherence
A fixed relationship between the phase of waves in beam of radiation of a single frequency. Two beams of light are coherent when the phase difference their waves is constant
Interference
The process in which two or more light, sound, or electromagnetic waves of the same frequency combine or reinforce or cancel each other, the amplitude of the resulting wave being equal to the sum of the amplitude of the combing waves
Monochromatic light
Light of a single wavelength
