University Physics Volume 3
17th Edition
ISBN: 9781938168185
Author: William Moebs, Jeff Sanny
Publisher: OpenStax
expand_more
expand_more
format_list_bulleted
Textbook Question
Chapter 7, Problem 38P
Suppose an electron is confined to a region of length 0.1 nm (of the order of the size of a hydrogen atom) and its kinetic energy is equal to the ground state energy of the hydrogen atom in
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
Consider an oxygen (O2) molecule in a bottle of air. Imagine that at a certain time, we locate the molecule along the x axis to within an uncertainty of 0.1 nanometers.
a) What is the minimum uncertainty in the molecule's x-velocity required by the Heisenberg Uncertainty Principle? (Hint: the answer is about 10 m/s)
b) How does this compare (roughly) to the magnitude of the molecule's average x-velocity due to its thermal motion at room temperature? (Hint: the answer is delta v << average thermal speed)
(Hint: Avogadro's number of oxygen molecules has a mass of about 32 grams. At an absolute temperature T, a molecule has an average kinetic energy of 1.5 * kB * T, where kB is Boltzmann's constant. Room temperature is about 295 K).
A 10.0 g marble is gently placed on a horizontal tabletop that is 1.75 m wide. (a) What is the maximum uncertainty in the horizon- tal position of the marble? (b) According to the Heisenberg uncertainty principle, what is the minimum uncertainty in the horizontal velocity of the marble? (c) In light of your answer to part (b), what is the longest time the marble could remain on the table? Compare this time to the age of the universe, which is approximately 14 billion years. (Hint: Can you know that the horizontal velocity of the marble is exactly zero?)
An electron is confined to a region of space of the size
of an atom (0.1 nm). (a) What is the uncertainty in the
momentum of the electron? (b) What is the kinetic energy
of an electron with a momentum equal to Ap? (c) Does
this give a reasonable value for the kinetic energy of an
electron in an atom?
Chapter 7 Solutions
University Physics Volume 3
Ch. 7 - Check Your Understanding If a=3+4i , what is the...Ch. 7 - Check Your Understanding Suppose that a particle...Ch. 7 - Check Your Understanding For the particle in the...Ch. 7 - Check Your Understanding A sodium atom nukes a...Ch. 7 - Check Your Understanding A particle With mass m is...Ch. 7 - Check Your Understanding Which of the following...Ch. 7 - Check your Understanding (a) Consider an infinite...Ch. 7 - Check Your Understanding The vibrational frequency...Ch. 7 - Check Your Understanding Find the expectation...Ch. 7 - Check Your Understanding A proton with kinetic...
Ch. 7 - What is the physical unit of a wave function,...Ch. 7 - Can the magnitude of a wave function (*(x,t)(x,t))...Ch. 7 - What kind of physical quamtity does a wave...Ch. 7 - What is the physical meaning of a wave function of...Ch. 7 - What is the meaning of the expression "expectation...Ch. 7 - If the formalism of quantum mechanics is 'more...Ch. 7 - Can the de Broglie wavelength of a particle be...Ch. 7 - Can we measure the energy of a free localized...Ch. 7 - Can we measure both the position and momentum of a...Ch. 7 - What is the difference between a wave function...Ch. 7 - If a quantum particle is in a stationary state,...Ch. 7 - Explain the difference between time-dependent and...Ch. 7 - Suppose a wave function is discontinuous at some...Ch. 7 - Using the quantum particle in a box model,...Ch. 7 - Is it possible that when we measure the energy of...Ch. 7 - For a quantum panicle in a box, the first excited...Ch. 7 - Is it possible to measure energy of 0.75h for a...Ch. 7 - Explain the connection between Planck's hypothesis...Ch. 7 - If a classical harmonic oscillator can at rest,...Ch. 7 - Use an example of a quantum particle in a box or a...Ch. 7 - Can we simultaneously measure position and energy...Ch. 7 - When an electron and a proton of the same kinetic...Ch. 7 - What decreases the tunneling probability most:...Ch. 7 - Explain the difference between a box-potential and...Ch. 7 - Can a quantum particle 'escape' from an infinite...Ch. 7 - A tunnel diode and a resonant-tunneling diode both...Ch. 7 - Compute |(x,t)|2 for the function (x,t)=(x)sint,...Ch. 7 - Given the complex-valued function...Ch. 7 - Which one of the following functions, and why,...Ch. 7 - A particle with mass m moving along the x-axis and...Ch. 7 - A wave function of a particle with mass m is given...Ch. 7 - A velocity measurement of an a-particle has been...Ch. 7 - A gas of helium atoms at 273 K is in a cubical...Ch. 7 - If the uncertainty in the y -component of a...Ch. 7 - Some unstable elementary particle has a rest...Ch. 7 - An atom in a metastable state has a lifetime of...Ch. 7 - Measurements indicate that an atom remains in an...Ch. 7 - Suppose an electron is confined to a region of...Ch. 7 - Combine Equation 7.17 and Equation 7.18 to show...Ch. 7 - Show that (x,t)=Aei(kwt) is a valid solution to...Ch. 7 - Show that (x,t)=Asin(kxt) and (x,t)=Acos(kxt) do...Ch. 7 - Show that when 1(x,t) and 2(x,t) are solutions to...Ch. 7 - A particle with mass m is described by the...Ch. 7 - Find the expectation value of the kinetic energy...Ch. 7 - Find the expectation value of the square of the...Ch. 7 - A free proton has a wave function given by...Ch. 7 - Assume that an electron in an atom can be treated...Ch. 7 - Assume that a proton in a nucleus can be treated...Ch. 7 - An electron confined to a box has the ground state...Ch. 7 - What is the ground state energy (in eV) of a...Ch. 7 - What is the ground state energy (in eV) of an a...Ch. 7 - To excite an election in a one-dimensional box...Ch. 7 - An electron confined to a box of width 0.15 nm by...Ch. 7 - If the energy of the first excited state of the...Ch. 7 - Suppose an electron confined to a emits photons....Ch. 7 - Hydrogen H2 molecules are kept at 300.0 K in a...Ch. 7 - An electron is confined to a box of width 0.25 nm....Ch. 7 - An electron in a box is in the ground state with...Ch. 7 - Show that the two lowest energy states of the...Ch. 7 - If the ground state energy of a simple harmonic...Ch. 7 - When a quantum harmonic oscillator makes a...Ch. 7 - Vibrations of the hydrogen molecule H2 can be...Ch. 7 - A particle with mass 0.030 kg oscillates back-and-...Ch. 7 - Find the expectation value x2 of the square of the...Ch. 7 - Determine the expectation value of the potential...Ch. 7 - Verify that given by Equation 7.57 is a solution...Ch. 7 - Estimate the ground state energy of the quantum...Ch. 7 - A mass of 0.250 kg oscillates on a spring with the...Ch. 7 - Show that the wave function in (a) Equation 7.68...Ch. 7 - A 6.0-eV electron impacts on a barrier with height...Ch. 7 - A 5.0-eV electron impacts on a barrier of with...Ch. 7 - A 12.0-eV electron encounters a barrier of height...Ch. 7 - A quantum particle with initial kinetic energy...Ch. 7 - A simple model of a radioactive nuclear decay...Ch. 7 - A muon, a quantum particle with a mass...Ch. 7 - A grain of sand with mass 1.0 mg and kinetic...Ch. 7 - Show that if the uncertainty in the position of a...Ch. 7 - The mass of a -meson is measured to be 770MeV/c2...Ch. 7 - A particle of mass m is confined to a box of width...Ch. 7 - A particle in a box [0; L] is in the third excited...Ch. 7 - A 0.20-kg billiard ball bounces back and forth...Ch. 7 - Find the expectation value of the position squared...Ch. 7 - Consider an infinite square well with wall...Ch. 7 - Consider an infinite square well with wall...Ch. 7 - Atoms in a crystal lattice vibrate in simple...Ch. 7 - A diatomic molecule behaves like a quantum...Ch. 7 - An electron with kinetic energy 2.0 MeV encounters...Ch. 7 - A beam of mono-energetic protons with energy 2.0...Ch. 7 - An electron in a long, organic molecule used in a...Ch. 7 - In STM, an elevation of the tip above the surface...Ch. 7 - If STM is to detect surface features with local...Ch. 7 - Use Heisenberg's uncertainty principle to estimate...Ch. 7 - Suppose an infinite square well extends from L/2...Ch. 7 - A particle of mass m confined to a box of width L...
Additional Science Textbook Solutions
Find more solutions based on key concepts
1. A person gets in an elevator on the ground floor and rides it to the top floor of a building. Sketch a veloc...
College Physics: A Strategic Approach (4th Edition)
3. Suppose the door of a room makes an airtight, but frictionless, fit in its frame. Do you think you could ope...
College Physics (10th Edition)
25. The 100 kg block in FIGURE EX7.25 takes 6.0 s to reach the floor after being released from rest. What is th...
Physics for Scientists and Engineers: A Strategic Approach, Vol. 1 (Chs 1-21) (4th Edition)
8. A 1000 kg car pushes a 2000 kg truck that has a dead battery. When the driver steps on the accelerator, the ...
Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (4th Edition)
The proton is a composite particle composed of three quarks, all of which are either up quarks (u; charge +23e)...
Essential University Physics: Volume 2 (3rd Edition)
Knowledge Booster
Similar questions
- (a) The position of an electron is known to within 14.5 Å (1.45×10-9 m). What is the minimum uncertainty in its velocity?(b) Repeat the calculation of part (a) for a helium atom.arrow_forwardProblem 2: An electron of momentum p is at a distancer from a stationary proton. The two particles are interacting via the electric Coulomb potential. If the electron is bound to the proton to form a hydrogen atom, its average position is at the proton, but the uncertainty in its position is approximately equal to the radius, r, of its orbit. The electron's average momentum will be zero, but the uncertainty in its momentum will be given by the uncertainty principle. Treat the atom as a one-dimensional system to solve the following questions. (a) Estimate the uncertainty in the electron's momentum in terms of r. (b) Estimate the electron's kinetic, potential, and total energies in terms of r. (c) The actual value of r is the one that minimizes the total energy, resulting in a stable atom. Find that value of r and the resulting total energy. Compare your answer with the predictions of the Bohr theory.arrow_forwardIf the position of an electron in a membrane is measured to an accuracy of 3.58 µm, what is the electron's minimum uncertainty in velocity (in m/s)? a) If the electron has this velocity, what is its kinetic energy in eV? b) What are the implications of this energy, comparing it to typical molecular binding energies?arrow_forward
- (Hand by writing ans.)A certain atom has an energy level of 3.50 eV above the ground state. When excited to this state, it remains 4.0µs, on average, before emitting a photon and returning to the ground state. i) What is the energy of the photon? What is the wavelength of the photon? ii) What is the smallest possible uncertainty in the energy of the photon?arrow_forwardA proton is known to be within an interval ±6 fm (the radius of a large nucleus). Roughly what is the minimum uncertainty in its velocity? Treat this problem as one-dimensional and express your answer as a fraction of c.arrow_forwardCalculate the lowest possible uncertainty in the velocity for an electron, (mass 9.11x1031 kg) where the position is known to an uncertainty of 1.0x1011m. Give your answerin units of 10° m/s to 3 decimals. Your Answer: Answerarrow_forward
- An atom is in an excited state for 4.00 us before moving back to the ground state. Find the approximate uncertainty in energy of the photon in units of 10¹¹ eV. (A) 8.23 (B) 3.78 (C) 4.97 (D) 5.49 (E) 6.17arrow_forwardAn electron with kinetic energy E = 3.10 eV is incident on a barrier of width L = 0.230 nm and height U = 10.0 eV (a) What is the probability that the electron tunnels through the barrier? (Use 9.11 10-31 kg for the mass of an electron, 1.055 ✕ 10−34 J · s for ℏ, and note that there are 1.60 ✕ 10−19 J per eV.) b) What is the probability that the electron is reflected? What If? For what value of U (in eV) would the probability of transmission be exactly 25.0% and 50.0%? c) 25.0% d) 50.0%arrow_forwardI need the answer as soon as possiblearrow_forward
- Imagine playing baseball in a universe (not ours!) where the Planck constant is 0.60 J s and thus quantum physics affects macroscopic objects. What would be the uncertainty in the position of a 0.50 kg baseball that is moving at 20 m/s along an axis if the uncertainty in the speed is 1.0 m/s?arrow_forwardAn atom in an excited state of 4.7 eV emits a photon and ends up in the ground state. The lifetime of the excited state is 1.0 x 10-13 s. (a) What is the energy uncertainty of the emitted photon? (b) What is the spectral line width (in wavelength) of the photon?arrow_forwardImagine another universe in which the value of Planck’s con- stant is 0.0663 J s, but in which the physical laws and all other physical constants are the same as in our universe. In this universe, two phys- ics students are playing catch. They are 12 m apart, and one throws a 0.25 kg ball directly toward the other with a speed of 6.0 m/s. (a) What is the uncertainty in the ball’s horizontal momentum, in a direction per- pendicular to that in which it is being thrown, if the student throwing the ball knows that it is located within a cube with volume 125 cm3 at the time she throws it? (b) By what horizontal distance could the ball miss the second students?arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
University Physics Volume 3PhysicsISBN:9781938168185Author:William Moebs, Jeff SannyPublisher:OpenStax
Modern PhysicsPhysicsISBN:9781111794378Author:Raymond A. Serway, Clement J. Moses, Curt A. MoyerPublisher:Cengage Learning
Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
Physics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
University Physics Volume 3
Physics
ISBN:9781938168185
Author:William Moebs, Jeff Sanny
Publisher:OpenStax
Modern Physics
Physics
ISBN:9781111794378
Author:Raymond A. Serway, Clement J. Moses, Curt A. Moyer
Publisher:Cengage Learning
Principles of Physics: A Calculus-Based Text
Physics
ISBN:9781133104261
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Physics for Scientists and Engineers with Modern ...
Physics
ISBN:9781337553292
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning