Physics for Scientists and Engineers
Physics for Scientists and Engineers
6th Edition
ISBN: 9781429281843
Author: Tipler
Publisher: MAC HIGHER
Question
Book Icon
Chapter 30, Problem 51P

(a)

To determine

The instantaneous Poynting vector.

(a)

Expert Solution
Check Mark

Answer to Problem 51P

The instantaneous Poynting vector is 1μ0c[E102(cos( k 1x ω 1t))E202(cos( k 2x ω 2tδ))]i^ .

Explanation of Solution

Given:

The electric field of first wave is E1=E10cos(k1xω1t)j^ .

The electric field of second wave is E2=E20cos(k2xω2t+δ)j^ .

Formula used:

The expression for instantaneous Poynting vector is given by,

  S=1μ0[E1+E2]×1c[[E1E2]i^]

Calculation:

The instantaneous Poynting vector is calculated as,

  S=1μ0[ E 1+ E 2]×1c[[ E 1 E 2]i^]=1μ0[( E 10cos( k 1 x ω 1 t) j ^)+( E 20cos( k 2 x ω 2 tδ) j ^)]×1c[( E 10cos( k 1 x ω 1 t) j ^)( E 20cos( k 2 x ω 2 tδ) j ^)]i^=1μ0c[E102(cos( k 1 x ω 1 t))E202(cos( k 2 x ω 2 tδ))]i^

Conclusion:

Therefore, the instantaneous Poynting vector is 1μ0c[E102(cos( k 1x ω 1t))E202(cos( k 2x ω 2tδ))]i^ .

(b)

To determine

The time averaged Poynting vector.

(b)

Expert Solution
Check Mark

Answer to Problem 51P

The time averaged Poynting vector is 12μ0c[E102E202]i^ .

Explanation of Solution

Calculation:

Consider the relation,

  S=1μ0c[E102(cos( k 1x ω 1t))E202(cos( k 2x ω 2t+δ))]i^

The time average of the square of the cosine term is 0.5 so, the time averaged Poynting vector is,

  Sav=12μ0c[E102E202]i^

Conclusion:

Therefore, the time averaged Poynting vector is 12μ0c[E102E202]i^ .

(c)

To determine

The instantaneous and time average Poynting vector.

(c)

Expert Solution
Check Mark

Answer to Problem 51P

The instantaneous and time averaged Poynting vector are 1μ0c[E102(cos( k 1x ω 1t))E202(cos( k 2x+ ω 2t+δ))]i^ and 12μ0c[E102E202]i^ respectively.

Explanation of Solution

Given:

The direction of propagation of second wave is E2=E20cos(k2x+ω2t+δ)j^ .

Calculation:

The instantaneous Poynting vector is calculated as,

  S=1μ0[ E 1+ E 2]×1c[[ E 1 E 2]i^]=1μ0[( E 10cos( k 1 x ω 1 t) j ^)+( E 20cos( k 2 x+ ω 2 t+δ) j ^)]×1c[( E 10cos( k 1 x ω 1 t) j ^)( E 20cos( k 2 x+ ω 2 t+δ) j ^)]i^=1μ0c[E102(cos( k 1 x ω 1 t))E202(cos( k 2 x+ ω 2 t+δ))]i^

The time averaged Poynting vector is,

  Sav=12μ0c[E102E202]i^

Conclusion:

Therefore, the instantaneous and time averaged Poynting vector are 1μ0c[E102(cos( k 1x ω 1t))E202(cos( k 2x+ ω 2t+δ))]i^ and 12μ0c[E102E202]i^ respectively.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
Fresnel lens: You would like to design a 25 mm diameter blazed Fresnel zone plate with a first-order power of +1.5 diopters. What is the lithography requirement (resolution required) for making this lens that is designed for 550 nm? Express your answer in units of μm to one decimal point. Fresnel lens: What would the power of the first diffracted order of this lens be at wavelength of 400 nm? Express your answer in diopters to one decimal point. Eye: A person with myopic eyes has a far point of 15 cm. What power contact lenses does she need to correct her version to a standard far point at infinity? Give your answer in diopter to one decimal point.
Paraxial design of a field flattener. Imagine your optical system has Petzal curvature of the field with radius p. In Module 1 of Course 1, a homework problem asked you to derive the paraxial focus shift along the axis when a slab of glass was inserted in a converging cone of rays. Find or re-derive that result, then use it to calculate the paraxial radius of curvature of a field flattener of refractive index n that will correct the observed Petzval. Assume that the side of the flattener facing the image plane is plano. What is the required radius of the plano-convex field flattener? (p written as rho )
3.37(a) Five free electrons exist in a three-dimensional infinite potential well with all three widths equal to \( a = 12 \, \text{Å} \). Determine the Fermi energy level at \( T = 0 \, \text{K} \).  (b) Repeat part (a) for 13 electrons.   Book: Semiconductor Physics and Devices 4th ed, NeamanChapter-3Please expert answer only. don't give gpt-generated answers, & please clear the concept of quantum states for determining nx, ny, nz to determine E, as I don't have much idea about that topic.
Knowledge Booster
Background pattern image
Similar questions
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
University Physics Volume 2
Physics
ISBN:9781938168161
Author:OpenStax
Publisher:OpenStax
Text book image
Glencoe Physics: Principles and Problems, Student...
Physics
ISBN:9780078807213
Author:Paul W. Zitzewitz
Publisher:Glencoe/McGraw-Hill
Text book image
Physics for Scientists and Engineers: Foundations...
Physics
ISBN:9781133939146
Author:Katz, Debora M.
Publisher:Cengage Learning
Text book image
Physics for Scientists and Engineers, Technology ...
Physics
ISBN:9781305116399
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Text book image
Principles of Physics: A Calculus-Based Text
Physics
ISBN:9781133104261
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Text book image
University Physics Volume 1
Physics
ISBN:9781938168277
Author:William Moebs, Samuel J. Ling, Jeff Sanny
Publisher:OpenStax - Rice University