p.1067

Ch 34 Electromagnetic Waves34.1 Displacement Current and the General Form

of Ampere’s Law

Id = 0dE/dt B·ds = 0(I + Id)

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. Ey = Emaxcos(kx – t)

b. Bz = Bmaxcos(kx – t)

3. Emax/Bmax = E/B = c

4. c = (1/00)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 = Emaxcos(kz – t) i. Its

magnetic field vector is

A. B = Bmaxcos(kz – t) j

B. B = Bmaxcos(ky – t) k

C. B = Bmaxcos(ky – t) i

D. B = Bmaxcos(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

Iav = EmaxBmax/20

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