PHY 2020 Lecture Notes - Lecture 39: Plane Wave, Total Internal Reflection, Radio Masts And Towers
Document Summary
To understand electromagnetic waves, the speed of light, and the electromagnetic spectrum. To characterize sinusoidal waves and determine their energy. To describe reflection, refraction, and total internal reflection. Electromagnetic waves: when either an eclectic or a magnetic field is changing with time, a field is changing with time, a field of the other kind is induced in adjacent region of space. In this way, time-varying electric and magnetic fields can propagate through apace from one region to another: such a propagating disturbance is called electromagnetic waves. An example: to produce its radio signal, a radio station sends an appropriately modulated alternating current into the antenna of its radio mast, the time-varying current creates changing electric and magnetic fields, and electromagnetic wave is emitted. A rudimentary electromagnetic wave: the electric and magnetic fields are uniform behind the advancing wave front and zero in front of it. Your fingers point in the direction of the b field.
