1. Wed. Mar. 4 – Physics Lecture #34 The Unification of Electricity and Magnetism 0. Announcements 1. Questions? 2. Electric Fields Accompany Changing Magnetic Fields, and Magnetic Fields Accompany Changing Electric Fields  Electromagnetic Radiation 3. Electric Fields and Magnetic Fields are Unified 4. More Unification

2. (Today) Wed. Mar. 4 All-Campus Mentoring Day (1 – 4), Academic Fair (4 – 6) http://www.evergreen.edu/events/mentoringdays/ Office Hours Rachel Wed 12 – 1 Krishna Thu 2 – 3Seth’s Tutoring Hours: see web-site Week 20 Schedule Mon. Mar. 9, 9 – noon, Lecture Hall 2: Physics Exam Tue. Mar. 10, 9 – noon, LIB 1005: Calculus Exam Tue. Mar. 10, 1 – 3:00, Lab 1 2046 Mandatory Lab Clean-up Physics Exam Group Reflection Wed. Mar. 11, 9 – 1, Lab 1 2046 Calculus Exam Group Reflection Self-Evaluation Peer Review Quarter Wrap-up Thu. Mar. 12: Portfolios due by 9 am outside Rachel’s office Lab 2 3268

3. A wire loop lies in the plane of the page as shown. A point P above the loop (in the plane of the page) is indicated. Consider the following directions, and hold up as many cards as apply: a)The current in the loop is clockwise and constant. What is the direction of the magnetic field at P ? The current in the loop now alternates (CW, then CCW, then CW, etc.) b)What is the direction of the EM wave at the indicated point? c)What is the polarization direction of the magnetic field portion of the EM wave at the indicated point? d)What is the direction of the electric field associated with the EM wave at the indicated point? How are the maximum values of the electric field and the magnetic field related? 1. Up3. Right5. Into page 2. Down4. Left6. Out of page 0. No direction/zero P

4. Maxwell discovered that this electromagnetic disturbance traveled at a speed determined by the electric and magnetic constants: This speed was

5. From WikiMedia Commons, permission granted by author Victor Blacus under a Creative Commons Attribution-Share Alike 3.0 Unported license. For waves: wave speed = (frequency) x (wavelength) v = f The longest wavelength that most people can see is 700 nm. What frequency corresponds to that wavelength?

6. Unification of Electricity & Magnetism  reveals EM waves  unifies Light & Optics w/ E&M  basis for incredible technical revolution  theoretical underpinnings sets stage for Special Relativity  experimental confirmation sets stage for Quantum Mechanics