Maxwell's Wave Equation

• Who published the paper relating electric and magnetic fields in 1864?

  James Clerk Maxwell
• What do Maxwell's equations predict about electric and magnetic fields?

  They predict oscillating electric and magnetic fields
• What are electromagnetic waves?

  Oscillating electric and magnetic fields

  
• What does a charged particle produce?

  An electric field
• How does an accelerating charge affect the electric field?

  It produces an alternating electric field
• What does the alternating electric field produce?

  A perpendicular alternating magnetic field
• What is self-propagation in electromagnetic waves?

  It is the continuous generation of fields
• What do electromagnetic waves not require to travel?

  A medium
• In an electromagnetic wave, what does the electric field's oscillation generate?

  A perpendicular oscillating magnetic field

  
• What is the formula for the speed of electromagnetic waves in a vacuum?

  $c =$$\frac{1}{\mu_0 \epsilon_0}$
• What do the constants μ and ε represent in Maxwell's formula?

  Permeability and permittivity of free space
• Why is the speed of electromagnetic waves in a vacuum constant?

  Because μ and ε are constants
• What does the permeability of free space relate to?

  Magnetic flux density and current
• What does the permittivity of free space relate to?

  Electric field strength and charge
• How did Maxwell calculate the speed of electromagnetic waves?

  Using known values for ε and μ
• What was Weber and Kohlrausch's measured speed of light?

  $3.107 \times 10^8 \text{ m/s}$
• How do you calculate Maxwell's value of the speed of light?

  Substitute ε and μ into the formula
• What is the difference between Maxwell's value and Weber and Kohlrausch's value of the speed of light?

  $1.08 \times 10^7 \text{ m/s}$
• How do you express the difference in speed as a percentage of Maxwell's value?

  Divide difference by Maxwell's value and multiply by 100%
• What is the percentage difference in the values of speed of light?

  3.60%
• What are the key constants in Maxwell's equations?

  • Permeability of free space (μ)
  • Permittivity of free space (ε)
• What are the implications of Maxwell's equations for electromagnetic waves?

  • Predict existence of electromagnetic waves
  • Describe self-propagation of waves
  • Establish speed of waves in vacuum
• What are the examiner tips regarding permittivity and permeability?

  • ε (epsilon) is electric
  • μ (mu) is magnetic
  • Check data booklet for symbols