Physics (hill) Flashcards
Properties of longitudinal waves and examples
They oscillate parallel
They become compressed or refracted when they travel through a medium p-waves and progressive waves
Properties of transverse waves and examples
They oscillate perpendicular
Have peaks(maximum) + troughs(minimum) when oscillating
Electromagnetic waves
What are progressive waves
Waves that move from an equilibrium to a new position
They oscillate and transfer energy not matter
Travel quick through earth
Definition of displacement
Distance from the the equilibrium position in a particular direction
Definition of amplitude
The maximum displacement from an equilibrium position
Definition of Wavelength
The minimum distance between 2 points (one peak to another)
Definition of period of oscillation
Time taken for one oscillation or time taken for a wave to move a whole wave length
Definition of frequency
Number of wave lengths passing a given point
Definition of wave speed
The distance travelled by a wave per second
Equation for refractive index
C=n/v
N is refractive index
C is the speed of light
V is vitacity of the the wave medium
Why must N be equal to or greater then 1
Or otherwise we would be travelling faster then the speed of light
What is phase difference
The degrees between two points on a wave of a wave length
What are the two equations of phase difference
P= X/lander * 360(degrees)
For phase difference in degrees
P= X/lander * 2pi
For phase difference in rad
What are the Materials you are meant to know the refractive index for
Vacuum (1)
Air (1)
Diamond (2.42)
Crown glass (1.52)
Olive oil (1.47)
Water (1.33)
What conditions must be met to use snells law
N1 > N2
Angle 1 > critical angle
What is diffraction
When a wave passes through a gap its spread out in different directions
All waves go through diffraction
Speed ,wavelength, frequency stay the same
What 2 quantities matter in diffraction
Wavelengths of wave
Size of gap or (obstacle)
What is polarisation and the 3 types
In a 3D world polarisation happens with transverse waves
If a wave vibrates in one plane its plane polarised
If a wave is reflected off a surface they become partially polarised
What allows optical fibres to be good at total internal reflection
The cladding has a lower index then core
What is intensity
The further we travel from light the less concentrated the energy
The dimmer the source looks
The equation for intensity
I = P/A
I = W/m^2
I = P/pi r^2
What is the law that links intensity and amplitude
Intensity = amplitude^2
Intensity always has to be positive
What are properties of em waves
They don’t need a medium to travel through
What is the electro magnetic spectrum in order
Radio waves
Micro waves
Infrared
Visible light
Ultra violet
X-rays
Gamma-rays
What’s the difference between x-rays and gamma ray s
X-rays come from fast moving electrons
Gamma unstable isotopes
What are radio waves wavelength
10^6 - 10^-1
What is the wave length of microwaves
10^-1 - 10^-3
What is the wave length of infrared
10^-3 - 7x10^-7
What is the wave length of visible light
7x10^-7 - 4x10^-7
What is the wavelength of ultraviolet
4x10^-7 - 10^-8
What is the wave length of x-rays
10^-8 - 10^-10
What is the wavelength of gamma rays
10^-10 - 10^-16
What is interference
The super position of waves causing an increase in or decrease in the amplitude of a wave
What type of wave can go through super position
It can be used on every wave as long as they are the same type
What happens When two waves interact
Two waves amplitude are in opposite directions then we can achieve destruction of waves
Two waves have the same amplitude are in the same direction we can achieve constructive waves
What is coherence
If two waves have a constant phase difference and Sam wavelength are coherent
What is path difference
The distance transverse by a wave to meet a particular point
What happens if a a source is closer to the wave
Chance of coherence decreases
What must two waves have in comman for it to produce a maximum
Phase difference of 0 or 2pi being in phase
Path difference is either 0 or a whole number
What must two waves have for them to produce a minimum
Phase difference - be in anti phase with each other
And a path difference that isnt a whole number
How are stationary waves formed
When two or more waves are supposed
What happens if two waves have the same frequency at a certain point an are stationary waves
If they are in anti phase displacement will cancel out
In phase full constructive
In between Anti phase and in phase leads to partial construction and destruction
What is a progressive wave
Transfer energy and not matter
What is a stationary waves
No net energy transfer
What is the wavelength of a stationary waves
Twice the distance between adjacent nodes/antinodes
When is a stationary waves in phase
All regions between 2 nodes on a standing wave are in phase
What is the shape of the first harmonic of a closed open system
Node anti node
What is the frequency of the first harmonic in a open closed system
F0
What is the wavelength of the first harmonic in a closed open system where L is length
4L
What are the number of wavelength present in the first harmonic
1/4 lander
What number should every open closed frequency times to give
4L
What should frequency and wavelength of a open open or closed close system be
2L
What is the shape of the first harmonic for a open open system or a closed closed
Open open - anti node anti node
Closed closed - node node
What are the number of wavelength for the first harmonic of a open open or closed closed system
1/2 Lander
What is the gradient of a stress strain graph
Young’s modulus
What order does a stress strain graph go
Limit of proportionality hooked law obeyed and returns to original shape
