Electromagnetic waves are often described as self-sustaining oscillations of electric…
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Waves Sound and Physical Optics · Waves Sound and Physical Optics
Problem
Electromagnetic waves are often described as self-sustaining oscillations of electric and magnetic fields that do not require a material medium.
(i) Describe, in logical steps, how a time-varying electric field gives rise to a magnetic field and how the resulting magnetic field in turn produces an electric field.
(ii) Illustrate the relative orientations of the electric field, magnetic field and direction of propagation for a plane electromagnetic wave travelling in free space.
(iii) Explain why such a mechanism allows electromagnetic waves to propagate through vacuum, whereas mechanical waves like sound cannot.