Introduction to quantum Mechanics

1. PLANKS
CONSTANT IN
ACTION
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2. CLASSICAL TO QUANTUM MECHANICS
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3. PHOTONS
• Particle like quanta of EM radiation
• Vphoton=c
•  p=h/ and E= hc/
• In comparison to macroscopic standards momentum and E of Photons are very small
e.g. for a photon of = 663 nm have p= 10-27 Js and E= 3 x 10-19 J
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4. EVIDENCE OF PARTICLE NATURE OF PHOTONS
• Compton effect says ,“Scattering process is a photon and electron collision”
• Increase in Wavelength is the
multiple of fundamental wavelength
known as “Compton Wavelength “ of
an electron
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5. EVIDENCE OF WAVE NATURE OF PHOTONS
• Young double slit experiment proved the wave nature of photons
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6. DE BROGLIE WAVES
• He proposed the possibility of matter as particle as well as wave i.e a particle can act as
a wave corresponding to a wavelength  as
• General relationship between relativistic energy ,p and m is
• Now
• Under ultra relativistic conditions mc2 is negligible so
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7. CONTINUED ………..
• For a non relativistic particle Where E (=p2/2m)is the KE of particle
• For such aparticle
• For an electron having mass 9.1 x10-31 kg
•  if E= 1.5 eV then =1nm and if E= 15KeV then =0.01nm
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8. ATOMS
• Energy of electron in nth state is
• Where n=1,2,3,4,…….
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9. EXISTANCE OF QUANTIZED STATES IN HYDROGEN
• Energy difference between Excited and ground state

10. MEASUREMENT
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• In classical Mechanics it is assumed that measurements are
precise so they do not disturb other quantities
• In Quantum Mechanics it is assumed that measurements are
not precise so measurement in 1 quantity can disturb the
other quantity measurement Heisenberg uncertainity
principle
• P .X ≈ ħ and E .t ≈ ħ
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