 # p.1067 Ch 34 Electromagnetic Waves 34.1 Displacement Current and the General Form of Ampere’s Law I d =  0 d  E /dt B·ds =  0 (I + I d ) 

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p.1067

Ch 34 Electromagnetic Waves 34.1 Displacement Current and the General Form of Ampere’s Law I d =  0 d  E /dt B·ds =  0 (I + I d ) 

P34.1 (p.971)

Ch 34 Electromagnetic Waves 34.2 Maxwell’s Equations

Ch 34 Electromagnetic Waves 34.3 Plane Electromagnetic Waves

Properties of EM Waves 1. Transverse a. E and B  propagation direction with E  B at all times b. Propagation direction: E x B 2. Sinusoidal a. E y = E max cos(kx – t) b. B z = B max cos(kx – t) 3. E max /B max = E/B = c 4. c = (1/ 0  0 ) 1/2      

P34.8 (p.971) P34.9 (p.971)

CT1: A planar electromagnetic wave is propagating through space. Its electric field vector is given by E = E max cos(kz – t) i. Its magnetic field vector is A. B = B max cos(kz – t) j B. B = B max cos(ky – t) k C. B = B max cos(ky – t) i D. B = B max cos(kz – t) k     

Ch 34 Electromagnetic Waves 34.4 Energy Carried by Electromagnetic Waves A. Poynting’s Vector S = E x B /  0 Intensity = Power / Area = S Propagation direction is the direction of S B. Average Intensity I av = E max B max /2 0 P34.16 (p.972)    

CT2: At a fixed point, P, the electric and magnetic field vectors in an electromagnetic wave oscillate at angular frequency . At what angular frequency does the Poynting vector oscillate at that point? A. 2 B.  C. /2 D. 4

Ch 34 Electromagnetic Waves 34.5 Momentum and Radiation Pressure p = U/c (absorbed wave – normal incidence) p = 2U/c (reflected wave – normal incidence) Pressure = S/c (absorbed wave – normal incidence) Pressure = 2S/c (reflected wave – normal incidence) P34.33 (p.973)

Ch 34 Electromagnetic Waves 34.7 The Spectrum of Electromagnetic Waves Maxwell’s Rainbow: c = f

CT3: A long wavelength EM wave has a A. higher frequency than a short wavelength EM wave B. the same frequency as a short wavelength EM wave C. lower frequency than a short wavelength EM wave

Polling Question: Which material would you like to review most? A. Exam 1 B. Exam 2 C. New Material

Polling Question: Which chapters from the Exam 1 material would you like to review most? A. 13 B. 23 C. 24 D. 25

Polling Question: Which chapters from Exam 2 material would you like to review most? A. 26 B. 27 C. 28 D. 29 E. 30

Polling Question: Which chapters from the new material would you like to review most? A. 31 B. 32 C. 33 D. 34

Polling Question: Which type of material would you like to review most? A. problems B. concept questions C. general principles

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