Exam 31: Alternating Current

Probability: The probability density for an electron that has passed through an experimental apparatus is shown in the figure. If 4100 electrons pass through the apparatus, what is the expected number that will land in a 0.10 mm-wide strip centered at x = 0.00 mm?

Three dimensional potential well: A three-dimensional potential well has potential U₀ = 0 in the region 0 < x < L, 0 < y < L, and 0 < z < L and infinite potential otherwise. The ground state energy of a particle in the well is E₀. What is the energy of the first excited state, and what is the degeneracy of that state?

Harmonic oscillator: An electron is confined in a harmonic oscillator potential well. What is the longest wavelength of light that the electron can absorb if the net force on the electron behaves as though it has a spring constant of 74 N/m? (m_el = 9.11 × 10^-31 kg, c = 3.00 × 10⁸ m/s, 1 eV = 1.60 × 10^-19 J, ħ = 1.055 × 10^-34 J ∙ s, h = 6.626 × 10^-34 J ∙ s)

Particle in a box: An electron is in an infinite square well that is 2.6 nm wide. What is the smallest value of the state quantum number n for which the energy level exceeds 100 eV? (h = 6.626 × 10^-34 J ∙ s, m_el = 9.11 × 10^-31 kg, 1 eV = 1.60 × 10^{-19 J})

Normalization: The wave function for an electron that is confined to x ≥ 0 nm is ψ(x) = a) What must be the value of b? (b) What is the probability of finding the electron in a 0.010 nm-wide region centered at x = 1.0 nm?

Normalization: The wave function for an electron that is confined to x ≥ 0 nm is ψ(x) = (a) What must be the value of A? (b) What is the probability of finding the electron in the interval 1.15 nm ≤ x ≤ 1.84 nm?

Particle in a box: A 10.0-g bouncy ball is confined in a 8.3-cm-long box (an infinite well). If we model the ball as a point particle, what is the minimum kinetic energy of the ball? (h = 6.626 × 10^-34 J ∙ s)

Particle in a box: A particle is confined to a one-dimensional box (an infinite well) on the x-axis between x = 0 and x = L. The potential height of the walls of the box is infinite. The normalized wave function of the particle, which is in the ground state, is given by ψ(x) = sin , with 0 ≤ x ≤ L. What is the maximum probability per unit length of finding the particle?

Particle in a box: The ground state energy of a particle in a one-dimensional infinite potential well of width 1.5 nm is 20 eV. The ground state energy of the same particle in a one-dimensional finite potential well with U₀ = 0 in the region 0 < x < 1.5 nm, and U₀ = 50 eV everywhere else, would be

Tunneling: An electron with kinetic energy 2.80 eV encounters a potential barrier of height 4.70 eV. If the barrier width is 0.40 nm, what is the probability that the electron will tunnel through the barrier? (1 eV = 1.60 × 10^-19 J, m_el = 9.11 × 10^-31 kg, h = 6.626 × 10^-34 J ∙ s)

Harmonic oscillator: The atoms in a nickel crystal vibrate as harmonic oscillators with an angular frequency of 2.3 × 10¹³ rad/s. The mass of a nickel atom is 9.75 × 10^-26 kg. What is the difference in energy between adjacent vibrational energy levels of nickel? (h = 6.626 × 10^-34 J ∙ s, ħ = 1.055 × 10^-34 J ∙ s, 1 eV = 1.60 × 10^-19 J)

Particle in a box: A particle is confined to a one-dimensional box (an infinite well) on the x-axis between x = 0 and x = L. The potential height of the walls of the box is infinite. The normalized wave function of the particle, which is in the ground state, is given by ψ(x) = sin , with 0 ≤ x ≤ L. What is the probability of finding the particle between x = 0 and x = L/3?

Tunneling: The energy of a proton is 1.0 MeV below the top of a 6.8-fm-wide energy barrier. What is the probability that the proton will tunnel through the barrier? (1 eV = 1.60 × 10^-19 J, m_proton = 1.67 × 10^-27 kg, ħ = 1.055 × 10^-34 J ∙ s, h = 6.626 × 10^-34 J ∙ s)

Particle in a box: An electron is bound in an infinite square-well potential (a box) on the x-axis. The width of the well is L and the well extends from x = 0.00 nm to In its present state, the normalized wave function of the electron is given by: ψ(x) = sin (2πx/L). What is the energy of the electron in this state? (h = 6.626 × 10^-34 J ∙ s, m_el = 9.11 × 10^-31 kg, 1 eV = 1.60 × 10^{-19 J})

Particle in a box: An electron is bound in an infinite well (a box) of width 0.10 nm. If the electron is initially in the n = 8 state and falls to the n = 7 state, find the wavelength of the emitted photon. (c = 3.00 × 10⁸ m/s, h = 6.626 × 10^-34 J ∙ s, m_el = 9.11 × 10^-31 kg)

Harmonic oscillator: If an atom in a crystal is acted upon by a restoring force that is directly proportional to the distance of the atom from its equilibrium position in the crystal, then it is impossible for the atom to have zero kinetic energy.

Particle in a box: A particle confined in a rigid one-dimensional box (an infinite well) of length 17.0 fm has an energy level and an adjacent energy level E_n+1 = 37.5 MeV. What is the value of the ground state energy? (1 eV = 1.60 × 10^-19 J)

Three dimensional potential well: A three-dimensional potential well has potential U₀ = 0 in the region 0 < x < L, 0 < y < L, and 0 < z < 2L and infinite potential otherwise. The ground state energy of a particle in the well is E₀. What is the energy of the first excited state, and what is the degeneracy of that state?

Normalization: Find the value of A to normalize the wave function ψ(x) =

Tunneling: A 3.10-eV electron is incident on a 0.40-nm barrier that is 5.67 eV high. What is the probability that this electron will tunnel through the barrier? (1 eV = 1.60 × 10^-19 J, m_el = 9.11 × 10^-31 kg, ħ = 1.055 × 10^-34 J ∙ s, h = 6.626 × 10^-34 J ∙ s)