Problem 9.23 (a) Shallow water is nondispersive; waves travel at a speed that is proportional to the square root of the depth. In deep water, however, the waves can't "feel" all the way down to the bottom-they behave as though the depth were pro- portional to λ. (Actually, the distinction between “shallow” and “deep” itself depends on the wavelength: If the depth is less than λ, the water is "shallow"; if it is substantially greater than λ, the water is "deep.") Show that the wave velocity of deep water waves is twice the group velocity. (b) In quantum mechanics, a free particle of mass m traveling in the x direction is described by the wave function (x,t) = Ae(px-Er)/h where p is the momentum, and E = p²/2m is the kinetic energy. Calculate the group velocity and the wave velocity. Which one corresponds to the classical speed of the particle? Note that the wave velocity is half the group velocity.

University Physics Volume 1
18th Edition
ISBN:9781938168277
Author:William Moebs, Samuel J. Ling, Jeff Sanny
Publisher:William Moebs, Samuel J. Ling, Jeff Sanny
Chapter16: Waves
Section: Chapter Questions
Problem 121AP: A sunbather stands waist deep in the ocean and observes that six crests of periodic surface waves...
icon
Related questions
Question
Problem 9.23
(a) Shallow water is nondispersive; waves travel at a speed that is proportional to
the square root of the depth. In deep water, however, the waves can't "feel"
all the way down to the bottom-they behave as though the depth were pro-
portional to λ. (Actually, the distinction between “shallow” and “deep” itself
depends on the wavelength: If the depth is less than λ, the water is "shallow";
if it is substantially greater than λ, the water is "deep.") Show that the wave
velocity of deep water waves is twice the group velocity.
(b) In quantum mechanics, a free particle of mass m traveling in the x direction is
described by the wave function
(x,t) = Ae(px-Er)/h
where p is the momentum, and E = p²/2m is the kinetic energy. Calculate the
group velocity and the wave velocity. Which one corresponds to the classical
speed of the particle? Note that the wave velocity is half the group velocity.
Transcribed Image Text:Problem 9.23 (a) Shallow water is nondispersive; waves travel at a speed that is proportional to the square root of the depth. In deep water, however, the waves can't "feel" all the way down to the bottom-they behave as though the depth were pro- portional to λ. (Actually, the distinction between “shallow” and “deep” itself depends on the wavelength: If the depth is less than λ, the water is "shallow"; if it is substantially greater than λ, the water is "deep.") Show that the wave velocity of deep water waves is twice the group velocity. (b) In quantum mechanics, a free particle of mass m traveling in the x direction is described by the wave function (x,t) = Ae(px-Er)/h where p is the momentum, and E = p²/2m is the kinetic energy. Calculate the group velocity and the wave velocity. Which one corresponds to the classical speed of the particle? Note that the wave velocity is half the group velocity.
Expert Solution
steps

Step by step

Solved in 2 steps with 6 images

Blurred answer
Similar questions
  • SEE MORE QUESTIONS
Recommended textbooks for you
University Physics Volume 1
University Physics Volume 1
Physics
ISBN:
9781938168277
Author:
William Moebs, Samuel J. Ling, Jeff Sanny
Publisher:
OpenStax - Rice University
Physics for Scientists and Engineers, Technology …
Physics for Scientists and Engineers, Technology …
Physics
ISBN:
9781305116399
Author:
Raymond A. Serway, John W. Jewett
Publisher:
Cengage Learning
University Physics Volume 2
University Physics Volume 2
Physics
ISBN:
9781938168161
Author:
OpenStax
Publisher:
OpenStax
Principles of Physics: A Calculus-Based Text
Principles of Physics: A Calculus-Based Text
Physics
ISBN:
9781133104261
Author:
Raymond A. Serway, John W. Jewett
Publisher:
Cengage Learning