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CHAPTER 4 (THE WAVELIKE PROPERTIES OF PARTICLE) - Coggle Diagram
CHAPTER 4
(THE WAVELIKE PROPERTIES OF PARTICLE)
Wave Particle Duality
Quantum Nature of Light
Particle attribute of light
essentially the manifestation of the quantum nature of things.
Quantum Nature of Particle
wave attribute of particle
Plank Constant as a measure of quantum effect
when h appears, quantum effects arise
, h NEVER appear as both theories
do not take into account of quantum effects.
quantum effects arise in microscopic system
approximately of the order 10-10 m or smaller
de Broglie's Postulate
should be a symmetry between matter and wave.
p = h/wavelength
E = hf
Matter wave is a Quantum Phenomena
also means wave proprtties of matter
difficult to observe for macroscopic system
smallness of h in the relation wavelength= h/p makes wave characteristic of particles hard to be observed.
when h ---> 0, wavelength becomes vanishingly
Electron Wave or Particle?
they are both, but not simultaneous
for example, coin with two faces. But one can only see one side of the coin but not the other at any instance.
also called wave particle duality
Heisenberg’s Uncertainty Principle
A particle is represented by a wave packet/pulse
wavepulse /wave packet is formed by adding many waves of different amplitudes and
real particle is localised in space,the wave representation of a particle has to be in the form of wave packet/wave pulse.
The product of the uncertainty in momentum (energy) and in position (time) is at least as large as Planck’s constant.
Uncertainty in the energy of a state
energy of a system also has inherent uncertainty
DE is dependent on the time interval Dt
energy of an object can be measured with infinite precision (DE=0) only if the object of system exists for an infinite time (Dt→infinity)
the uncertainty in energy must be correspondingly greater
Conjugate variables
px,x}, {E,t} are called conjugate variables
px is the conjugate of x (and vice versa).
E is the conjugate to t (and vice versa).
The conjugate variables cannot in principle be measured (or known) to infinite precision simultaneously.
Experimental Evidences
double slit experiment
Davisson Gremer experiment