PHY1008- Quantum Mechanics for Engineers, Study notes of Physics

Download PHY1008- Quantum Mechanics for Engineers and more Study notes Physics in PDF only on Docsity!

PHY1008 - Quantum Mechanics for

Engineers

Unit 1 - Origin of Quantum Theory

GD Goenka University, Haryana

1/

Course Outcomes

• Understanding the alignment between Course Outcomes (COs), Program Outcomes (POs), and Program-Specific Outcomes (PSOs) is crucial for academic planning and assessment.
• This mapping ensures that the course content and activities contribute to the overall program goals.
• The table illustrates the mapping as per AICTE guidelines.

2/

Introduction

Introduction

• Quantum mechanics is the foundation of modern physics, chemistry, and biology.
• Explains phenomena such as blackbody radiation, the photoelectric effect, and Compton scattering.
• Introduces wave-particle duality and quantization of energy.

4/

Classical Concepts

• Classical physics: particles characterized by energy E and momentum p.
• Waves: described by amplitude and wave vector k.
• Classical physics failed to explain microscopic phenomena.

5/

Introduction to Quantum

Mechanics

Particle Aspect of Radiation

Particle Aspect of Radiation

• Classical physics distinguishes particles and waves.
• Particles have energy E and momentump⃗.
• Waves have amplitude and wave vector ⃗k.
• Classical physics fails to explain microscopic phenomena like blackbody radiation, photoelectric effect, and Compton effect.

7/

Blackbody Radiation

• When heated, solid objects emit thermal radiation.
• The radiation has a continuous frequency distribution.
• Blackbody: an idealized object that absorbs all radiation and emits radiation when heated.
• The radiation emitted by a blackbody is called blackbody radiation.

8/

Experimental Observations

Experimental Observations

• At equilibrium, blackbody radiation has a continuous energy distribution.
• The spectral energy density u(ν, T ) of blackbody radiation depends on frequency ν and temperature T.
• The energy density shows a pronounced maximum at a specific frequency, which increases with temperature.
• Classical physics failed to explain the observed spectral distribution.

10/

Classical Theories and Failures

Planck’s Quantum Hypothesis

Planck’s Quantum Hypothesis

• Max Planck proposed that energy exchange between radiation and matter occurs in discrete amounts called quanta.
• The energy of a quantum is given by E = hν, where h is Planck’s constant.
• Planck’s formula for spectral energy density:

u(ν, T ) =^8 πν

2 c^3

hν ehν/kT^ − 1

• This formula accurately explained the experimental data and marked the birth of quantum mechanics.

12/