Mumbai University Sem-1 Physics Easy-to-understand Notes

Quantum Physics

Kumkum Sanyal

Applied Physics Section
Thadomal Shahani Engineering College.
Bandra West, Mumbai - 400050



April 4, 2021

, Unit 01 : Quantum Physics

Prerequisites :
( Photoelectric effect, Dual nature of radiation, Matter
waves-wave nature of particles, de-Broglie relation,
Davisson-Germer experiment).
Contents :
• de Broglie hypothesis of matter waves
• Properties of matter waves, wave packet
• Phase velocity and Group velocity
• Wave function and it’s Physical interpretation
• Heisenberg uncertainty principle
• Schrodinger’s time dependent and time independent wave
equation
• Particle trapped in one dimensional infinite potential well

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, de Broglie Hypothesis

• All moving objects are associated with waves.
• These waves are known as matter waves.
• de Broglie wavelength λ = h
p
Here h →Planck’s constant, 6.63x10−34 J.s.
and p = mv → momentum of the particle.
• de Broglie wavelength thus relates the particle nature with
the wave nature of matter.
• de Broglie wavelength for
1. An accelerated charge particle λ = √ h
2mqV
q → charge, V → potential difference.
h
2. A particle in thermal equilibrium λ = √3mK
BT
KB →Boltzman constant; T →temperature in absolute scale.
3. A particle with kinetic energy K.E λ = √ h
2m(K.E)


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