Engineering Physics - Detailed Notes

Graphic Era Hill University

  • Established by an Act of the State Legislature of Uttarakhand (Adhiniyam Sankhya 12 of 2011).
  • Recognized as a university under section 2(f) of the UGC Act, 1956.

Course Information

  • Course: Engineering Physics
  • Course Code: TPH 201
  • Instructor: Dr. Vishal Chauhan

Units Covered

  1. Interference and Diffraction
  • Conditions for interference
  • Coherence
  • Bi-prism experiment
  • Newton's rings
  • Fraunhofer diffraction at single slit and multiple slits
  • Rayleigh's criteria of resolution
  1. Polarisation, Laser, and Fibre Optics
  2. Special Theory of Relativity
  3. Superconductivity and Electromagnetism
  4. Quantum Mechanics

Unit I: Interference and Diffraction

Interference
  • Conditions for Interference:
  • Coherent sources
  • Similar amplitude, wavelength, frequency
  • Specific spatial relationships
  • Coherence: Temporal and spatial coherence evaluated.
Diffraction
  • Fraunhofer Diffraction: Explained through single and multiple slits, introducing diffraction grating and resolving power.

Historical Contributions to Physics

  • 17th Century:
  • Thales of Miletus: Charge observations
  • William Gilbert: Magnetic attraction and needle behavior
  • 18th Century:
  • Isaac Newton:
    • Published "OPTICKS" on light behavior.
    • Proposition of light's rectilinear propagation
  • Johannes Kepler: Light laws and propagation Principles.
  • 19th Century:
  • [Key Figures] Thomas Young, Faraday, Oersted, etc.
  • 20th Century: Development of unified theories in physics, focusing on quantum mechanics and electromagnetism.

Electromagnetism

  • Unification of electricity, magnetism, and optics through key experiments.
  • Key Theorists: Faraday and Maxwell demonstrated relationships between light and electromagnetic theory.

Wave Motion

  • Types of Waves:
  • Mechanical Waves: Require a medium (e.g., sound waves).
  • Electromagnetic Waves: Propagate through space without a medium (e.g., light).
  • Matter Waves: Exhibit wave properties (e.g., electrons).
  • Simple Harmonic Motion (SHM):
  • Defined as motion with acceleration proportional to displacement and directed towards a fixed point.
  • Represented graphically (sinusoidal motion).

Principle of Superposition

  • Multiple waves propagate simultaneously in the same medium; the resultant displacement is the vector sum of individual displacements.

Interference Patterns

  • Conditions for Sustained Interference:
  • Reliable sources, specific amplitude, and distance between them.
  • Intensity Variation: Analyzed using equations for maximum/minimum intensity based on amplitude and phase relationships.

Fringe Width

  • Calculations:
  • Wavelength relationships in interference patterns (constructive/destructive).
  • Methods to compute fringe width in various setups analyzed (e.g., biprism experiment).
  • Practical Application: Example problems related to fringe width calculations with coherent sources.

Fresnel's Bi-prism Experiment

  • Experimental setup to determine wavelength (A) and fringe width, assessing two methods of calculation:
  1. Displacement Method.
  2. Deviation Method.

Summary of Physics Principles

  • Discussion of key principles and applications within physics, highlighting historical progress from early theories to unified theories in electromagnetism
  • Emphasizing hands-on experimental approaches to reinforce theoretical knowledge.