/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 33 In the ground state of hydrogen,... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

In the ground state of hydrogen, the uncertainty in the position of the electron is roughly \(0.10 \mathrm{~nm}\). If the speed of the electron is approximately the same as the uncertainty in its speed, about how fast is it moving?

Short Answer

Expert verified
The electron is moving at a speed of approximately \(5.77 \times 10^5 m/s\).

Step by step solution

01

- Understand Heisenberg's Uncertainty Principle

The Heisenberg’s Uncertainty Principle is given by \( \Delta x \Delta p \geq \frac{h}{4\pi} \), where \( \Delta x \) is the uncertainty in position, \( \Delta p \) is the uncertainty in momentum, \( h \) is Planck’s constant. Since it's given that the uncertainty in the speed is approximately equal to the speed of the electron itself, we can substitute momentum (\( p \)) with \( m_e v \), where \( m_e \) is the mass of electron and \( v \) is the speed of electron.
02

- Substitute the Known Values

Substituting \( \Delta x = 0.10 \times 10^{-9} m \), \( \hbar = \frac{h}{2\pi} = 1.05457 \times 10^{-34} Js \), and \( m_e = 9.10938356 \times 10^{-31} kg \) into the Heisenberg’s Uncertainty Principle, one gets \( \Delta v = \frac{h}{4\pi \Delta x m_e} \) as the equation derived to find the uncertainty in speed.
03

- Solve for \( \Delta v \)

Now solve the equation for \( \Delta v \), substituting the known values, we get \( \Delta v = \frac{1.05457 \times 10^{-34} Js}{4\pi \times 0.10 \times 10^{-9} \times 9.10938356 \times 10^{-31} kg} \), which simplifies to \( \Delta v ≈ 5.77 \times 10^5 m/s \).

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Quantum Mechanics
Quantum mechanics is the branch of physics that deals with the behavior of particles at the atomic and subatomic levels, where the classical laws of motion do not apply. It provides a mathematical framework for understanding the physical properties of particles such as electrons, protons, and photons. At this scale, particles exhibit wave-particle duality, meaning they display properties of both waves and discrete particles.

One of the most profound implications of quantum mechanics is the Heisenberg Uncertainty Principle. It states that there is a fundamental limit to the precision with which certain pairs of physical properties, such as position and momentum, can simultaneously be known. This is not due to inadequacies in measurement, but rather a reflection of the intrinsic nature of quantum systems. Thus, the more precisely one property is measured, the less precisely the other can be known. This principle introduces an inherent indeterminacy into quantum systems and challenges the deterministic viewpoint of classical physics.

In applying the uncertainty principle as seen in the exercise, when dealing with particles like electrons, we cannot determine their exact position and velocity at the same time. This has significant implications for understanding the behavior of atoms and molecules, and is essential in predicting the statistical distribution of an electron's position and velocity in an atom like hydrogen in its ground state.
Physical Properties of Electrons
Electrons are subatomic particles with a negative electrical charge and a mass that is a fraction of that of protons and neutrons. They play a vital role in the chemical bonds between atoms and in electrical current, among other things. Electrons occupy atomic orbitals, which are regions of space around the nucleus of an atom where the probability of finding an electron is highest. As opposed to a deterministic trajectory, an electron in an orbital is better described by a wave function, which informs us of the electron’s probable location rather than a precise path.

Wave-Particle Duality

Electrons exhibit wave-particle duality, behaving as both particles and waves. This means they can be described by the principles of both classical mechanics and quantum mechanics, depending on the context. Experiments such as the double-slit experiment reveal the wave-like nature of electrons. This dual nature becomes particularly relevant when measuring the physical properties of electrons, as in the exercise mentioned, where treating electrons as waves helps explain why there's an uncertainty in their position and velocity.

Quantum States

Furthermore, electrons exist in quantum states that are defined by quantum numbers representing different energy levels and orbitals. These states determine the physical properties such as the energy, angular momentum, and magnetism of the electron. Understanding these states is critical to many technologies, including lasers, semiconductors, and medical imaging devices.
Ground State of Hydrogen
The ground state of a hydrogen atom is the lowest energy state of the atom, with the electron in the closest orbital to the nucleus, known as the 1s orbital. The term 'ground state' refers to the natural, unexcited state of an atom, where the electron has the lowest possible energy. In hydrogen, this is where the electron is most likely to be found because it’s the most stable configuration.

When we talk about the ground state, we can refer to both the energy of the electron and its probable position, as determined by its wave function. In quantum mechanics, each electron state is described by a set of quantum numbers, and for the ground state of hydrogen, these numbers reveal that the electron occupies the spherically symmetrical s-orbital.

The uncertainty principle applies even to electrons in the ground state. As the exercise shows, you cannot fully determine where the electron is and how fast it is moving at the same time. The exercise simulates the situation by considering an uncertainty in the electron's position to calculate the uncertainty in its speed, illustrating the limitations set by the principles of quantum mechanics in predicting the exact behavior of electrons in atoms, even in their most stable form.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

How fast must an electron be moving if all its kinetic energy is lost to a single \(x\) -ray photon (a) at the high end of the x-ray electromagnetic spectrum with a wavelength of \(1.00 \times 10^{-8} \mathrm{~m}\) and \((\mathrm{b})\) at the low end of the x-ray electromagnetic spectrum with a wavelength of \(1.00 \times 10^{-13} \mathrm{~m} ?\)

Calculate the minimum-wavelength \(\mathrm{x}\) -ray that can be produced when a target is struck by an electron that has been accelerated through a potential difference of (a) \(15.0 \mathrm{kV}\) and (b) \(1.00 \times 10^{2} \mathrm{kV}\). (c) What happens to the minimum wavelength as the potential difference increases?

Photons of wavelength \(450 \mathrm{~nm}\) are incident on a metal. The most energetic electrons ejected from the metal are bent into a circular arc of radius \(20.0 \mathrm{~cm}\) by a magnetic field with a magnitude of \(2.00 \times 10^{-5} \mathrm{~T}\). What is the work function of the metal?

When light of wavelength \(350 \mathrm{~nm}\) falls on a potassium surface, electrons having a maximum kinetic energy of \(1.31 \mathrm{eV}\) are emitted. Find (a) the work function of potassium, (b) the cutoff wavelength, and (c) the frequency corresponding to the cutoff wavelength.

The work function for platinum is \(6.35 \mathrm{eV}\). (a) Convert the value of the work function from electron volts to joules. (b) Find the cutoff frequency for platinum. (c) What maximum wavelength of light incident on platinum releases photoelectrons from the platinum's surface? (d) If light of energy \(8.50 \mathrm{eV}\) is incident on zinc, what is the maximum kinetic energy of the ejected photoelectrons? Give the answer in electron volts. (e) For photons of energy \(8.50 \mathrm{eV}\), what stopping potential would be required to arrest the current of photoelectrons?

See all solutions

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.