MODULE- 2: QUANTUM MECHANICS
1. Dual nature of matter (de-Broglie Hypothesis)
Light sometimes behaves as wave (as exhibited by phenomenon like interference,
diffraction, superposition) and sometimes as particle (as exhibited by phenomenon like
photoelectric effect and Compton Effect). This is called wave-particle duality of light.
Since nature loves symmetry, if the light radiation behaves as particles under certain
conditions and as waves under certain conditions, then material particles (like atoms,
molecules, electrons, protons, neutrons, etc) must also exhibit dual nature. This is known
as de-Broglie hypothesis or Dual nature of matter or Wave particle duality. This was
proposed Louis de Broglie in 1923. According to de-Broglie hypothesis, “Every moving
particle is associated with waves called as de-Broglie waves or matter waves or pilot
waves”. The wavelength ‘λ’ of a de-Broglie wave associated with particle of mass ‘m’
moving with velocity 'v' is
h h
= =
p mv
2. Different forms of de-Broglie wavelength
, 3. Properties of matter or de-Broglie waves
1. Matter waves are produced by the motion of the particles and are independent of the
1. Dual nature of matter (de-Broglie Hypothesis)
Light sometimes behaves as wave (as exhibited by phenomenon like interference,
diffraction, superposition) and sometimes as particle (as exhibited by phenomenon like
photoelectric effect and Compton Effect). This is called wave-particle duality of light.
Since nature loves symmetry, if the light radiation behaves as particles under certain
conditions and as waves under certain conditions, then material particles (like atoms,
molecules, electrons, protons, neutrons, etc) must also exhibit dual nature. This is known
as de-Broglie hypothesis or Dual nature of matter or Wave particle duality. This was
proposed Louis de Broglie in 1923. According to de-Broglie hypothesis, “Every moving
particle is associated with waves called as de-Broglie waves or matter waves or pilot
waves”. The wavelength ‘λ’ of a de-Broglie wave associated with particle of mass ‘m’
moving with velocity 'v' is
h h
= =
p mv
2. Different forms of de-Broglie wavelength
, 3. Properties of matter or de-Broglie waves
1. Matter waves are produced by the motion of the particles and are independent of the
