1. 4/12/06 Electromagnetic Waves and Radio Friday’s Reading: Section 13.2: Microwave Ovens (pp. 432 – 438) Upcoming Reading Assignments: Section 14.1: Sunlight (pp. 445 – 453) Section 14.2: Discharge Lamps (pp. 454 – 463) Section 14.3: Lasers and LEDs (pp. 464 – 470) Section 15.1: Cameras (pp. 478 – 488) Section 15.2: Optical Recording and Communication (pp. 489 – 497) Poster Session Meetings Schedule appointment Change/Modify your topic Plan your poster Etc.

2. Types of Memory Magnetic (information stored in orientation of poles) Flash (information stored in charge on transistor’s “floating gates”) Optical (discuss later in course)

3. Electric and Magnetic Fields Sources of Electric Field?Sources of Magnetic Field? Accelerated Charges

4. Electromagnetic Waves & Electromagnetic Spectrum Figure from Tipler & Mosca, “Physics for Scientists and Engineers”, 5 th edition, p. 977 Exercise: Visible light is a small portion of the electromagnetic spectrum. The wavelengths of visible light range from 400 nm (violet) to about 780 nm (red). What is the range of frequencies of visible light? (1 nm = 10 -9 m)

5. Direction of EM Waves & Polarization EM wave made up of Electric field and Magnetic field E perpendicular to B Direction of wave perpendicular to E and B Exercise: The Electric field part of an EM wave oscillates IN and OUT of the screen. What are possible directions of the Magnetic field part of this EM wave? Follow-up Exercise: An EM wave is moving to the LEFT. At some instant at some point, the Electric field points OUT of the screen. At this instant at this point, what is the direction of the Magnetic field?

6. Making a Radio Wave