Quantum Physics Flashcards
what did maxwell propose
what does comptons effect only depend on
Maxwell proposed the converse: a changing electric field has
a magnetic field associated with it.
what does comptons effect only depend on
the Compton shift, depends only on the scattering angle 0, and not
on the initial wavelength A
what are wave packets and what is, group velocity
a group of superposed waves which together form a travelling localized disturbance,
its the velocity of a representative point on the wave packet
is the rate at which the phase of the wave propagates in space. It represents the velocity at which a single point of constant phase (such as a crest or trough) moves.
group velocity is the velocity of the full packet
position momentum uncertainty
energy time uncertainty
uncertainty relation for circular motion
the position of a particle and momentum of a particle cannot be determined simultaneously with unlimited precision
energy
the energy and life of a particle in a state cannot be determined simultaneously with unlimited precision
circular motion
the angular position and angular momentum of a particle in a circular motion cannot be determined simultaneously with unlimited precision
what is Significance of the Poynting Vector
Poynting vector represents the direction and magnitude of energy flow in an electromagnetic wave
gives the rate of energy transfer per unit area for an electromagnetic wave
Its direction points along the direction in which energy propagates.
Poynting vector helps calculate the total energy flowing through a surface.
What the signifiance/intrpretation of wave function/Normalization of wave functions
What is borns rule
Probability density
The square of the absolute value of the wave function, or |ψ|2, represents the probability density of finding a particle in a specific location at a given time = 1.
Or probability of finding the particle in unit volume in
three dimensional space
Quantum state
The wave function represents the quantum state of a system, such as an atom or particle.
wave packet 𝚿 is a
probability amplitude
* The wavefunction carries information about the system
wave function is the probability amplitude
The wave function evolves according to the Schrödinger equation, which allows for the prediction of future probabilities.
BORNS RULE
The Born Rule in Quantum Mechanics is mathematically expressed as P = |ψ|²,
what is plane polarised, circular, eliptical,unpolorised light
A plane wave is called linearly polarized. horizontall
and vertically linearly polarized same phase/amplitude at a 45 degrees
If light is composed of two plane waves of equal amplitude but differing
in phase by 90°, then the light is said to be circularly polarized
If two plane waves of differing amplitude are related in phase by 90°, or
if the relative phase is other than 90° then the light is said to be
elliptically polarized
what is black body
found materials which absorb all incident rays
Such a material on heating would emit all wavelengths of radiation
absorbed
OR
bodies that have surfaces which absorb all the thermal radiation incident upon them.
what is classical wave theory assumption
what was the UV cathostrophe
Assumed that energy content of the wave is
proportional to the square of the amplitude of the waves
UV
Rayleigh and Jeans showed that the
number of modes was proportional to ν^2
also Rayleigh and Jeans considered the average energy of the
oscillators as per Maxwell-Boltzmann distribution law
as E = kBT
although the curves agree at low frequencies, classical physics predicted too much energy at high frequencies, leading to the ultraviolet catastrophe.
what conclusion did max plancks have regarding the average energy of the oscillators
how is energy determined for particle-particle interaction of EM radiation
the collection of harmonic oscillators of
different frequencies and the energy of the radiations has to be packets
of hν or nhv and thus it was related with the experimental values
particle-particle
Energy is quantized in terms of hν
Wavelength and frequency - effect on energy
KE of matter particles like electrons
what is the value of the compton shift h/MoC
and what is the value of h dash
p^2/2m
2.42410^-12
1.05510^-34
In a non-dispersive medium the group velocity is equal to the phase velocity (TRUE, OR FALSE)
TRUE, all frequency components of a wave travel at the same speed. Therefore, the group velocity (velocity at which the wave packet or energy propagates) is equal to the phase velocity (velocity at which the phase of the wave propagates).
what are the formula/normalization of wave function
1) mathematical form = ψ Ae^i/ℏ(Px-Et)
2)intrepretation/sigificance of borns rule ψψ
3) A or finding normalization constant such that integral of - infinity to infinity ψψ leads to normalization
properties of wave function
ψ must be continious, single value, finite, at a single place
dψ/dx (slope) must be continous, single value and and finite
ψ must be normalizable
if ψ represents a wave packet centered at x=0 then as x = infinity ψ=0
Explain the concept normalization
what is probability density
Normalization refers to the process of multiplying a wave function by a suitable
constant or adjusting its amplitude such that
integral - ∞ to + ∞ Ψ*Ψ dx =1
to ensure that the total probability of finding the particle in all possible positions is 1
prob density
Probabilty density is defined by ψ*ψ and is the probability per unit length ( for 1D case)
what is observable
what are eigen values
what are eigen functions
what are mathematical operators
An observable is any physical quantity that can be measured in a quantum system, such as position, momentum, energy,
Eigen values
Eigenvalues are the possible values that can be obtained when measuring an observable. They are solutions to the eigenvalue equation:
EIGEN FUNCTIONS
An eigenfunction (or eigenstate) is a specific wavefunction that remains unchanged except for a scaling factor when acted upon by an operator representing an observable. The eigenvalue associated with the eigenfunction represents the value of the observable. operator = cap on top
MATHEMATICAL OPERATORS
Mathematical operators can be used to extract
information about the physical state in form of
observables, like momentum, particles position or energy
