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7. EM Waves in Vacuum. The differential form of Gauss’s law is ρ
∇·E =
0
where ∇ · E is called the divergence of E and can be expressed in rectangular
coordinates as
∇·E = ∂∂∂
,
,
∂x ∂y ∂z · (Ex , Ey , Ez ) = ∂ Ex
∂ Ey
∂ Ez
+
+
∂x
∂y
∂z Suppose that a plane EM wave travels in the +x direction in vacuum (ρ= 0). Then
electric field components are functions of (x – ct):
E = f (x − ct)ˆ + g (x − ct)ˆ + h(x − ct)ˆ
x
y
z
Physics 2214, Spring 2012 3 Cornell University TA's Name:_____________________________________Section: ____
Your Name: ____________________________________
What does Gauss’s law let you conclude about the functions f, g, and/or h? (You
can use Gauss's law for magnetic fields to make a similar conclusion about B .)
8. Faraday’s law and EM waves. Consider Faraday’s law
∂B
∇×E =−
∂t Suppose that the magnetic field points in the y direction (such that Bx and Bz are
zero), and that the electric field is of the form
E = f (x − ct)ˆ + g (x − ct)ˆ + h(x − ct)ˆ
x
y
z
as in problem 4. What does Faraday’s law allow you to conclude about E ? Questions, Exercises and Problems from Y&F 12th Ed. for study and review:
(Do not turn these in!)
Volume 1, Chapter 15:
Questions 13, 16, 18
Exercises 21, 24
Problems 63, 64, 65, 66, 81, 84
Volume 1, Chapter 16:
Questions: 17, 18, 20
Exercises 17, 19, 21, 22, 43, 44, 46, 49, 50
Problems 74, 75, 77, 79, 80
Volume 2, Chapter 32:
Questions 32.1, 32.6 32.9, 32.10.
Exercises 2, 6, 8, 9, 35
Problems 36, 55 Physics 2214, Spring 2012 4 Cornell University...
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This note was uploaded on 02/27/2013 for the course PHY 2214 taught by Professor Davis during the Spring '12 term at Cornell University (Engineering School).
 Spring '12
 Davis
 Energy, Power

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