PHYS20040:
From Classical to Modern Physics

Welcome back!

From Classical to Modern Physics

Course organisation

  • Runs through entire year
  • Multiple assessments
  • Problems classes (formative)
  • Summative Assessments
    • Four problem sets - see Blackboard for deadlines
    • December exam
    • Final exam

TB1

  • Special Relativity -
    Sotiria Fotopoulou
  • Electricity & Magnetism -
    Adrian Barnes
  • Light phenomena -
    Sotiria Fotopoulou
  • Lectures:
    3 hours / week
  • Problems class:
    1 hour / week1

Schedule

Contact me

  • Sotiria Fotopoulou
  • Office 3.11
  • sotiria.fotopoulou@bristol.ac.uk

Resources

  • Main text: ‘Introduction to electrodynamics’ by D. Griffiths
  • Optional:
    • For historical context:
      ‘A student’s guide to Einstein’s Major Papers’ by R. E. Kennedy
    • For fun: Einstein’s papers
  • Further reading:
    • ‘Feynman Lectures on Physics’ by Feynman, Leighton, Sands
    • Tipler and Mosca, Chapters R and 39
    • Special Relativity by A P French

Physics in early 20th century

Mechanics

  • Known and understood for more than 200 yrs.
  • Newton’s Laws:
    • 1st law: every body remains in its state at being at rest or moving uniformly, unless it is compelled to change its state by external forces.
    • 2nd law: a change in motion is proportional to the force impressed.
    • 3rd law: to any action there is always an opposite and equal reaction.

Electricity & Magnetism

  • Electricty & Magnetism where beeing experimentally explored and new phenomena emerged.
  • Maxwell’s equations
  • Speed of light is a constant: \(c=\frac{1}{\sqrt{\mu_0\epsilon_0}}\)
    • \(\mu_0\): permittivity of free space
    • \(\epsilon_0\): permeability of free space

Quantum theory

  • Quantum theory was making its appearance.
  • M. Planck, 1900: black-body radiation
    • electromagnetic energy is exchanged in quantized form

Thermodynamics

  • Thermodynamics view of the world was being developed.
    • states of mater
    • links heat, work, temperature
    • statistical description of population of particles

Special Theory of Relativity

1905: Einstein’s Annus Mirabilis

  • Four major papers:
    • Photoelectric effect
    • Brownian motion
    • SR I: ‘on the electrodynamics of moving bodies’
    • SR II: ‘does the inertia of a body depend upon its energy content?’

SR I: Einstein’s postulates

Principle of relativity

The laws of Physics apply in all inertial frames of reference.

Universal speed of light

The speed of light in vacuum is the same for all inertial observers, regardless of the motion of the light source.

Inertial Frames of reference

Definition
  • A frame in which Netwon’s laws hold.
  • If Newton’s laws apply in a frame, they also apply in every reference frame in uniform translational motion with respect to the first.

Inertial Frames of reference

Galilean transformations