Quantum Flashcards
What is the event horizon
The minimum distance from which light can just escape
What is schwarzchild radius
The distance from the singularity to the event horizon
Why is the sun is not a black hole
The radius of the sun is greater than the schwartzchild radius.
What is non-inertial frame of reference
Frame of reference that is accelerating
What happens to the time when the gravitational field becomes stronger
The time becomes slower
What is the Equivalent Principle
It is not possible to distinguish between the effects of an obsver of a uniform gravitational field and of a constant acceleration.
What does the world line look like on a graph for constant speed below C
Straight line above the speed of light line
What does the worldline look like for a stationary
Straight line vertically
What does the worldline look like for an acceleration
A curved like going right
Deacceleartion going craved up
What does the worldline for deacceleartaion look like
Curved to the left
Box grid
Top right - future even +ve
Bottom right - past event + ve
Top left - future event -ve
Bottom left - past event - ve
Geodisic
The path with the shortest distance between two points
What does Quanta mean
An exact amount
What is a blackbody
A perfect emitter or absorber of radiation at all wave lengths
What does each line on the absorption and emisson spectra
The frequency of the photon emitted or absorbed as an electron moves between spefic enegery levels
What is the photoelectric effect
When the light is incident on a metal plate and electron emitted
What can be explained through quantum physics but not classical
Blackbody radiation
Formation of emisson and absorption spectra
The photoelectric effect
Example of a black body
Stars
Sun
What does the blackbody spectrum show
Shows the range of wavelength of light emitted at different temperatures
What does the distribution or shape of the curve on the black body spectrum
The maximum wavelength is at the maximum irridnace going left depends on temperature
What is the problem with the black body spectrum
Classical theory couldn’t account for this distribution for the ultra violet because it was calculated it would tend to infinity. But practically it showd otherwise
What experimental data illustrated that the UV part of the spectrum the irridiamce would decrease, what did the mathematical side predicted
The uv would tend to infinity
What evidence shows that the math is incorrect
That it didn’t match what we measured practically
What was the ‘realisation’ about classical electromagnetic theory as a result of the ultraviolet catastrophe
They contradicted eachother and therefore a different physics was needed
What did bohr model use
It made a guess that angular momentum is quanised meaning it can only have spefic valued within the levels
What is mvr equal to in the equation
The angular momentum of electrons
Use the equation E=PC to get p=h/landa
P=E/c = hf/fwavelength =h/ wavelength
What is broglie wavelength equal too
Wavelength accosiated with a particle
What happens when electrons are passed through a crystal lattice
They diffraction qnd create a radical interference pattern
What is the pattern when electrons are diffracted
Light and dark spots
The higher the voltage
The more energy and greater peak intensity
Using heisenberg uncertainty principles the more accurately you know the position
The less accurately you know the momentum and vise versa
Some neutrons used to investigate the structure of crystal lattices will not produce interference patterns this may be due to a large uncertainty in the momentumb
Explain why a large uncertainty in the momentum would result in these neutrons being unsuitable for this diffraction process
The uncertainty in the position will be too small. Neutrons can be considered a particles even on the length of the scale
Quantum physics tunnelling
An object such as an electron or atom passing through a potential energy barrier. That according to classical physics should not be passable. Due to the object not having energy to pass
Where does the lowest enegey comic rays arrive from
The sun in a stream of charged particles
What Is solar wind
Cosmic rays in streams of charged particles
The origin of higher engery
Is made difficulty at they twist and turn in the magnetic fields of interstellar space
Where does solar wind come from
Upper atmosphere of the sun
Explain why the charged particles follow a helical path
The charged particles have a component parallel to the magnetic field whichoves them forward in that direction whichever it in a circle
What to solar wind normally consist of
Electrons protons and alpha particles
What are the two parts of the helical motions
The parallel to magnetic field
Perpendicular to magnetic field.
Parallel
Vcos0
Perpendicular
Vsin0
What direction does the particles have to be traveling in Inord3r to have a force excepted kn it by the field
Perpendicular
Will the compoent velocity that is parallel to the magnetic feild
No force
What is the pitch t
The distance between successive loops
Explain how a particle can follow a helical path rather than a circular one
The velocity perpendicular to the magnetic field produces circular motion
The velocity parallel to the field is constant and results in no unbalanced forced / unaffected by the magnetic feild
State two changes to the helical path followed by the proton as it approaches the pole
Radius decreases
Pitch decreases
What is quantum tunnelling
A quantum particle can exist in a position that according to classical physics it has insufficient engery to occupy.
What is quantum tunnelling
A quantum particle can exist in a position that according to classical physics it has insufficient engery to occupy.
State what is meant by plane-polarised light
Light oscillates in a single plane
What does polarisation relate too
Relates to the orientation of the electric field vibration
What is an unpolaired wave
The plane of an electric field constantly changes and can oscillate in any plane
Polaired waves
The plane of an electric field vibrating in a fixed in one direction
Is the reflected beam is completely plane polarised or not
Yes it is
Go over the derived snells law equation
Yes
How can sunlight be polarised
By passing it through a polariser
What is a polariser
It is a filter that has alot of very thin closely packed parallel lines on it that only allows the electric vector through one plane.
What is a analyser
It I’d a second filter excalty like the polariser
What does the analyser allow
Ut can be rotated to allow the plane polarised light through it or block it
What does the transmission depend on
The orientation of the analyser
When is their no light transmission through
When the analyser is at 90°
What happens to the light as the angle moves from 0° to 90°
The light intensity gradually falls yo 0
What happens to the light intensity as the angle increase from 90° to 180°
The light intensity gradually increases until maximum potential
How xan unpolarirsed light be plane polarised
By reflecting from any flat transparent electrical insulator
What does the degree of polarisation depend on
The angle of incidence and the refractive index of the material
Give me the derivation for brewster angle
N = sini/sinr
Angle of incidence = angle of reflection
180= I +90 +0r
R= 0r =(90-i)
N=sini/sin(90-i)
N=sini/cosi
N=tani
While watching a 3D movie a pair of glasses contain two polarisation filters one in each eye. Explain how this arranent enable a different image to be seen in each eye?
The filter for each eye will allow light from one projector image to pass through while blocking the light from the other projector
What is meant by plane polarised light
Light oscillates in a single plane
When is a electromagnetic wave is formed
When a electric feild combines with magnetic field. The feild oscillates in phase and perpendicular to eachother and the direction of motion
Permeability of free space
A measure of the amount of resistance encountered when firing a magnetic field in a vacuum
Permittivity ot free space
A constant that gives a measure of the ability of electric fields to pass through a vacuum
What is angular momentum
Can only have exact values
Explain how the divers sunglasses reduce the glare from the puddle of water
Sunglasses transmission axis is perpendicular to the plant of the polarised light
Explain why the brightness of the rainbow varies as described
Light from the rainbow is polarised. The plane of the polaired light gradually changes
