Question 1

The crystalline structure known as hexagonal close-packed

Accepted Answer

A) is characterized by the stacking of identical spheres. 
B) occurs when every ion has eight nearest-neighbor ions of opposite charge. 
C) corresponds to an alternating pattern of ions. 
D) occurs when an ion of either kind has six nearest neighbors of the other kind. 
E) None of these is correct. 
A) is characterized by the stacking of identical spheres. 
B) occurs when every ion has eight nearest-neighbor ions of opposite charge. 
C) corresponds to an alternating pattern of ions. 
D) occurs when an ion of either kind has six nearest neighbors of the other kind. 
E) None of these is correct.

Question 2

The resistivity of iron at 20ºC is 10 $\times$ 10-8 $\Omega$ · m and the number of electrons per cubic centimeter is 17.0 $\times$ 1022.If you take the average speed of the electrons to be equal to their root-mean-square speed (at T = 300 K)of 1.17 $\times$ 105 m/s,it follows that their mean free path,$\lambda$ ,must be

Accepted Answer

A) 0.245 nm 
B) 0.317 nm 
C) 0.428 nm 
D) 0.556 nm 
E) None of these is correct. 
A) 0.245 nm 
B) 0.317 nm 
C) 0.428 nm 
D) 0.556 nm 
E) None of these is correct.

Question 3

The frequency of the current observed at a Josephson junction is 345 MHz.The voltage applied to the junction to produce this current was

Accepted Answer

A) 1.43 µV 
B) 1.43 V 
C) 0.715 µV 
D) 0.715 mV 
E) 1.28 µV 
A) 1.43 µV 
B) 1.43 V 
C) 0.715 µV 
D) 0.715 mV 
E) 1.28 µV

Question 4

The classical theory of conduction

Accepted Answer

A) fails because electrons are not classical particles. 
B) does not take into account the scattering of electron waves by a lattice. 
C) fails to correctly describe the collision of an electron with a lattice ion. 
D) predicts a Maxwell-Boltzmann-like distribution of electron velocities. 
E) is described by all of these. 
A) fails because electrons are not classical particles. 
B) does not take into account the scattering of electron waves by a lattice. 
C) fails to correctly describe the collision of an electron with a lattice ion. 
D) predicts a Maxwell-Boltzmann-like distribution of electron velocities. 
E) is described by all of these.

Question 5

The classical free-electron theory of metals

Accepted Answer

A) correctly predicts the resistivity of a conductor but fails to predict the correct temperature dependence of the resistivity. 
B) correctly predicts both the resistivity of a conductor and its temperature dependence. 
C) incorrectly predicts the resistivity of a conductor but correctly predicts its temperature dependence. 
D) incorrectly predicts both the resistivity of a conductor and its temperature dependence. 
E) correctly predicts which materials are conductors,insulators,or semiconductors. 
A) correctly predicts the resistivity of a conductor but fails to predict the correct temperature dependence of the resistivity. 
B) correctly predicts both the resistivity of a conductor and its temperature dependence. 
C) incorrectly predicts the resistivity of a conductor but correctly predicts its temperature dependence. 
D) incorrectly predicts both the resistivity of a conductor and its temperature dependence. 
E) correctly predicts which materials are conductors,insulators,or semiconductors.

Question 6

Which of the following statements is false?

Accepted Answer

A) The behavior of free electrons in a metal is very different from the behavior of the molecules in an ordinary gas. 
B) Ordinary gas molecules are described by the classical Maxwell-Boltzmann energy distribution function. 
C) The main features of a Fermi electron gas can be understood by assuming an electron in a metal to be a particle in a box. 
D) No two electrons in an atom can be in the same quantum state. 
E) None of these is false. 
A) The behavior of free electrons in a metal is very different from the behavior of the molecules in an ordinary gas. 
B) Ordinary gas molecules are described by the classical Maxwell-Boltzmann energy distribution function. 
C) The main features of a Fermi electron gas can be understood by assuming an electron in a metal to be a particle in a box. 
D) No two electrons in an atom can be in the same quantum state. 
E) None of these is false.

Question 7

The average energy of a Fermi electron gas at T = 0 is

Accepted Answer

A) 3kT/2 
B) EF  
C) kT 
D) zero 
E) 3EF/5 
A) 3kT/2 
B) EF  
C) kT 
D) zero 
E) 3EF/5

Question 8

If you want to produce an amorphous solid from a liquid,you

Accepted Answer

A) cool the liquid slowly so that the molecules gradually lose their kinetic energy and thus form a maximum number of bonds. 
B) cool the liquid rapidly to remove its internal energy before the molecules have a chance to form many bonds. 
C) maintain the temperature of the liquid while increasing the pressure applied to the liquid. 
D) maintain the temperature of the liquid while decreasing the pressure applied to the liquid. 
E) warm the liquid while decreasing its pressure. 
A) cool the liquid slowly so that the molecules gradually lose their kinetic energy and thus form a maximum number of bonds. 
B) cool the liquid rapidly to remove its internal energy before the molecules have a chance to form many bonds. 
C) maintain the temperature of the liquid while increasing the pressure applied to the liquid. 
D) maintain the temperature of the liquid while decreasing the pressure applied to the liquid. 
E) warm the liquid while decreasing its pressure.

Question 9

According to the BCS theory,

Accepted Answer

A) electrons in a superconductor are coupled in pairs at low temperatures. 
B) electrons in a Cooper pair have equal and opposite spins. 
C) electrons in a Cooper pair act as a single particle with zero spin. 
D) any number of Cooper pairs may be in the same quantum state with the same energy. 
E) All of these are true. 
A) electrons in a superconductor are coupled in pairs at low temperatures. 
B) electrons in a Cooper pair have equal and opposite spins. 
C) electrons in a Cooper pair act as a single particle with zero spin. 
D) any number of Cooper pairs may be in the same quantum state with the same energy. 
E) All of these are true.

Question 10

Use the following to answer the question.  
-The graph that represents the Fermi factor F is

Accepted Answer

A) 1 
B) 2 
C) 3 
D) 4 
E) 5 
A) 1 
B) 2 
C) 3 
D) 4 
E) 5

Question 11

Molecules in a liquid

Accepted Answer

A) have little influence on one another. 
B) have little influence on one another except during their frequent but brief collisions. 
C) are close together and exert forces on one another that are comparable to the forces that bind atoms into molecules. 
D) form temporary short-range bonds that continually break and re-form due to the thermal kinetic energy of the molecules. 
E) are always arranged in a crystalline structure. 
A) have little influence on one another. 
B) have little influence on one another except during their frequent but brief collisions. 
C) are close together and exert forces on one another that are comparable to the forces that bind atoms into molecules. 
D) form temporary short-range bonds that continually break and re-form due to the thermal kinetic energy of the molecules. 
E) are always arranged in a crystalline structure.

Question 12

In the classical free-electron theory of metals,

Accepted Answer

A) a metal is pictured as a regular three-dimensional array of atoms or ions. 
B) a metal contains a large number of electrons that are free to move throughout the whole metal. 
C) thermal equilibrium is maintained by collisions of electrons with the lattice ions. 
D) electrons in the absence of an electric field move about the metal much as gas molecules move in a container. 
E) All of these are true. 
A) a metal is pictured as a regular three-dimensional array of atoms or ions. 
B) a metal contains a large number of electrons that are free to move throughout the whole metal. 
C) thermal equilibrium is maintained by collisions of electrons with the lattice ions. 
D) electrons in the absence of an electric field move about the metal much as gas molecules move in a container. 
E) All of these are true.

Question 13

Use the following to answer the question below: 
 
-The probability that an energy state in magnesium 0.05 eV below the Fermi energy is occupied at T = 300 K is

Accepted Answer

A) 5.52% 
B) 20.6% 
C) 47.1% 
D) 87.4% 
E) 99.9% 
A) 5.52% 
B) 20.6% 
C) 47.1% 
D) 87.4% 
E) 99.9%

Question 14

The crystalline structure known as face-centered-cubic

Accepted Answer

A) is characterized by the stacking of identical spheres. 
B) occurs when every ion has eight nearest-neighbor ions of opposite charge. 
C) corresponds to an alternating pattern of ions. 
D) occurs when an ion of either kind has six nearest neighbors of the other kind. 
E) None of these is correct. 
A) is characterized by the stacking of identical spheres. 
B) occurs when every ion has eight nearest-neighbor ions of opposite charge. 
C) corresponds to an alternating pattern of ions. 
D) occurs when an ion of either kind has six nearest neighbors of the other kind. 
E) None of these is correct.

Question 15

If the energy levels of a Fermi gas is given by En = nE1,the total energy of seven fermions in the ground state is

Accepted Answer

A) 7E1 
B) 9E1 
C) 11E1 
D) 14E1 
E) 16E1 
A) 7E1 
B) 9E1 
C) 11E1 
D) 14E1 
E) 16E1

Question 16

The crystal structure of a substance can be determined using X-ray diffraction.It can also be determined using neutron scattering.What is the kinetic energy of a neutron that has a wavelength of 0.1 nm?

Accepted Answer

A) 0.14 eV 
B) 0.082 eV 
C) 0.034 eV 
D) 0.23 eV 
E) 0.38 eV  
A) 0.14 eV 
B) 0.082 eV 
C) 0.034 eV 
D) 0.23 eV 
E) 0.38 eV

Question 17

Use the following to answer the question: 
 
-The Fermi energy in three dimensions at T = 0 is given by   The Fermi energy for aluminum is approximately

Accepted Answer

A) 11.7 eV 
B) 3.24 eV 
C) 5.53 eV 
D) 2.11 eV 
E) 9.46 eV 
A) 11.7 eV 
B) 3.24 eV 
C) 5.53 eV 
D) 2.11 eV 
E) 9.46 eV

Question 18

A semiconductor for which it is true that the major charge carriers are holes

Accepted Answer

A) is called an n-type semiconductor. 
B) is called a p-type semiconductor. 
C) accepts positive charges from filled valence bands. 
D) is devoid of acceptor levels. 
E) None of these is correct. 
A) is called an n-type semiconductor. 
B) is called a p-type semiconductor. 
C) accepts positive charges from filled valence bands. 
D) is devoid of acceptor levels. 
E) None of these is correct.

Question 19

A metal is a good conductor because the valence energy band for electrons is

Accepted Answer

A) empty. 
B) completely full. 
C) full,but there is only a small gap to a higher empty band. 
D) partly full. 
E) None of these is correct. 
A) empty. 
B) completely full. 
C) full,but there is only a small gap to a higher empty band. 
D) partly full. 
E) None of these is correct.

Question 20

Use the following to answer the question below: 
 
-The speed of a conduction electron whose energy is equal to the Fermi energy EF for magnesium is

Accepted Answer

A) 1.42 $\times$ 106 m/s 
B) 1.84 $\times$ 106 m/s 
C) 1.21 $\times$ 106 m/s 
D) 2.03 $\times$ 106 m/s 
E) 1.58 $\times$ 106 m/s 
A) 1.42 $\times$ 106 m/s 
B) 1.84 $\times$ 106 m/s 
C) 1.21 $\times$ 106 m/s 
D) 2.03 $\times$ 106 m/s 
E) 1.58 $\times$ 106 m/s

Exam 38: Solids and the Theory of Conduction

The crystalline structure known as hexagonal close-packed

The frequency of the current observed at a Josephson junction is 345 MHz.The voltage applied to the junction to produce this current was

The classical theory of conduction

The classical free-electron theory of metals

Which of the following statements is false?

The average energy of a Fermi electron gas at T = 0 is

If you want to produce an amorphous solid from a liquid,you

According to the BCS theory,

Use the following to answer the question. -The graph that represents the Fermi factor F is

Molecules in a liquid

In the classical free-electron theory of metals,

Use the following to answer the question below: -The probability that an energy state in magnesium 0.05 eV below the Fermi energy is occupied at T = 300 K is

The crystalline structure known as face-centered-cubic

If the energy levels of a Fermi gas is given by En = nE1,the total energy of seven fermions in the ground state is

The crystal structure of a substance can be determined using X-ray diffraction.It can also be determined using neutron scattering.What is the kinetic energy of a neutron that has a wavelength of 0.1 nm?

Use the following to answer the question: -The Fermi energy in three dimensions at T = 0 is given by The Fermi energy for aluminum is approximately

A semiconductor for which it is true that the major charge carriers are holes

A metal is a good conductor because the valence energy band for electrons is

Use the following to answer the question below: -The speed of a conduction electron whose energy is equal to the Fermi energy EF for magnesium is

Systems of Measurement

Motion in One Dimension

Motion in Two and Three Dimensions

Newtons Laws

Applications of Newtons Laws

Work and Energy

Conservation of Energy

Systems of Particles and Conservation of Linear Momentum

Rotation

Conservation of Angular Momentum

Gravity

Static Equilibrium and Elasticity

Fluids

Oscillations

Wave Motion

Superposition and Standing Waves

Temperature and the Kinetic Theory of Gases

Heat and the First Law of Thermodynamics

The Second Law of Thermodynamics

Thermal Properties and Processes

The Electric Field I: Discrete Charge Distributions

The Electric Field Ii: Continuous Charge Distributions

Electric Potential

Capacitance

Electric Current and Direct-Current Circuits

The Magnetic Field

Sources of the Magnetic Field

Magnetic Induction

Alternating-Current Circuits

Maxwells Equations and Electromagnetic Waves

Properties of Light

Optical Images

Interference and Diffraction

Wave Particle Duality and Quantum Physics

Applications of the Schrodinger Equation

Atoms

Molecules

Relativity

Nuclear Physics

Elementary Particles and the Beginning of the Universe

Filters

If the energy levels of a Fermi gas is given by E_n = nE₁,the total energy of seven fermions in the ground state is

Use the following to answer the question below: -The speed of a conduction electron whose energy is equal to the Fermi energy E_F for magnesium is