2.1 Waves Flashcards
2 types of waves
Longitudinal
Transverse
Longitudinal wave
Vibration of the particles/medium is parallel to the direction of energy flow
E.g. sound
Transverse wave
Vibration of the particles/medium is perpendicular to the direction of energy flow
E.g. water waves
Travelling/progressive wave
Wave which transfers energy away from the source in the medium without transferring the medium itself
Frequency
Number of vibrations/oscillations per second
Hz
Wavelength
Distance between 2 successive points on a wave that are in phase
Unit: m
Period
Time for one complete oscillation
Unit: s
Amplitude
Maximum displacement of a particle from its rest position
Unit: m
In phase
When peaks line up with peaks and troughs line up with troughs
What is the term used when peaks line up with phase?
Waves are completely out of phase
Phase difference of 2 waves
Distance between peak of one wave and the peak of another wave
Formula to work out phase difference
Difference/1 cycle
Polarisation
Name given to process of confining a transverse wave to vibrations that are in one plane
Unpolarised light
Vibrations in all possible directions perpendicular to the direction of transfer of energy
Polarised light
Light which has oscillations in one plane only
Why can longitudinal waves not be polarised?
No plane of vibration so they can’t be polarised
Properties of all electromagnetic waves
Can travel in a vacuum
Travel at the same speed in a vacuum - speed of light
Transverse waves
Can be refracted, reflected, polarised and detracted
Defracted
Ability to bend around a corner
Typical frequency of gamma rays
> 3x10 19
Typical frequency of x-rays
3x10 16 - 3x10 19
Typical frequency of ultra violet
7.5x10 14 - 3x10 16
Typical frequency for visible light
4x10 14 - 7.5x10 14
Typical frequency for infra-red radiation
3x10 11 - 4x10 14
Typical frequency for microwaves
3x10 9 - 3x10 11
Typical frequency for radio waves
<3x10 9
Order of waves in electromagnetic spectrum from low frequency, long wavelength to high frequency, short wavelength
radio waves
microwaves
infra-red
visible light
ultra-violet
x-rays
gamma rays
Order of waves in electromagnetic spectrum from high frequency, short wavelength to low frequency, long wavelength
gamma rays
x-rays
ultra-violet
visible light
infra-red
microwaves
radio waves
Typical wavelength of gamma rays
> 1x10 -11
Typical wavelength of x-rays
1x10 -8 - 1x10 -11
Typical wavelength of ultra violet
4x10 -7 - 1x10 -8
Typical wavelength of visible light
7.7x10 -7 - 4x10 -7
Typical wavelength of infrared radiation
1x10 -3 - 7.5x10 -7
Typical wavelength of microwaves
0.1 - 1x10 -3
Typical wavelength of radiowaves
<0.1
In nanometres, what is the typical wavelength of visible light?
400-700 nm
What is the wavelength of red light in nanometres?
700
What is the wavelength of violet light in nanometres?
400
