Question 1

The frequency of the current observed at a Josephson junction is 976 MHz.The voltage applied to the junction to produce this current was

Accepted Answer

A) 202 µV 
B) 1.43 V 
C) 1.43 µV 
D) 2.02 µV 
E) 1.28 µV 
A) 202 µV 
B) 1.43 V 
C) 1.43 µV 
D) 2.02 µV 
E) 1.28 µV

Question 2

Forward biasing of a pn junction

Accepted Answer

A) lowers the potential across a junction and increases the diffusion of holes and electrons. 
B) raises the potential across a junction and increases the diffusion of holes and electrons. 
C) raises the potential across a junction and decreases the diffusion of holes and electrons. 
D) lowers the potential across a junction and decreases the diffusion of holes and electrons. 
E) None of these is correct. 
A) lowers the potential across a junction and increases the diffusion of holes and electrons. 
B) raises the potential across a junction and increases the diffusion of holes and electrons. 
C) raises the potential across a junction and decreases the diffusion of holes and electrons. 
D) lowers the potential across a junction and decreases the diffusion of holes and electrons. 
E) None of these is correct.

Question 3

Insulators are poor conductors of electricity because

Accepted Answer

A) there is a small energy gap between the valence band and the next higher band in which electrons can collect. 
B) there is a large energy gap between the valence band and the next higher band in which electrons can collect. 
C) the valence band has a few vacancies for electrons. 
D) the valence band is only partly full. 
E) None of these is correct. 
A) there is a small energy gap between the valence band and the next higher band in which electrons can collect. 
B) there is a large energy gap between the valence band and the next higher band in which electrons can collect. 
C) the valence band has a few vacancies for electrons. 
D) the valence band is only partly full. 
E) None of these is correct.

Question 4

Use the following to answer the question.  
-The graph that represents the Fermi energy distribution function n(E)is

Accepted Answer

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

Question 5

If the atoms are treated as solid spheres,the fraction of volume occupied by the atoms in a face-centered-cubic unit cell is

Accepted Answer

A) 0.45 
B) 0.52 
C) 0.65  
D) 0.68 
E) 0.74  
A) 0.45 
B) 0.52 
C) 0.65  
D) 0.68 
E) 0.74

Question 6

KF has a face-centered-cubic lattice structure and the equilibrium spacing between the K+ and F- ions is 0.269 nm.It has a dissociation energy of 498 kJ/mol.The constant n in the empirical potential energy,Urep = A/rn,is

Accepted Answer

A) 2.2 
B) 4.3 
C) 5.8 
D) 6.9 
E) 8.7  
A) 2.2 
B) 4.3 
C) 5.8 
D) 6.9 
E) 8.7

Question 7

The molecules in a solid

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 8

If you apply a voltage of 3 µV to a Josephson junction,you can expect to measure a frequency of

Accepted Answer

A) 145 MHz 
B) 1450 MHz 
C) 346 kHz 
D) 346 Hz 
E) 527 Mhz 
A) 145 MHz 
B) 1450 MHz 
C) 346 kHz 
D) 346 Hz 
E) 527 Mhz

Question 9

The free-electron model of metals gives a good account of electrical conduction if

Accepted Answer

A) the classical mean speed vav is replaced by the Fermi speed uF. 
B) the collisions between electrons and the lattice ions are interpreted in terms of the scattering of electron waves. 
C) the collisions between electrons and the lattice ions are interpreted in terms of the scattering of hard spheres. 
D) the classical mean speed vav is retained in the model and the collisions between electrons and the lattice ions are interpreted in terms of the scattering of electron waves. 
E) the classical mean speed vav is replaced by the Fermi speed uF and the collisions between electrons and the lattice ions are interpreted in terms of the scattering of electron waves. 
A) the classical mean speed vav is replaced by the Fermi speed uF. 
B) the collisions between electrons and the lattice ions are interpreted in terms of the scattering of electron waves. 
C) the collisions between electrons and the lattice ions are interpreted in terms of the scattering of hard spheres. 
D) the classical mean speed vav is retained in the model and the collisions between electrons and the lattice ions are interpreted in terms of the scattering of electron waves. 
E) the classical mean speed vav is replaced by the Fermi speed uF and the collisions between electrons and the lattice ions are interpreted in terms of the scattering of electron waves.

Question 10

The crystalline structure known as body-centered-cubic

Accepted Answer

A) is characterized by the stacking of identical spheres. 
B) occurs when each 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 each 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 11

The classical free-electron theory of metals is inadequate in that it

Accepted Answer

A) assumes the average energy of the electrons to be 3kT/2. 
B) assumes the energy distribution to be a Maxwell-Boltzmann distribution. 
C) fails to incorporate the exclusion principle. 
D) assumes the applicability of the equipartition theorem. 
E) incorporates all of these. 
A) assumes the average energy of the electrons to be 3kT/2. 
B) assumes the energy distribution to be a Maxwell-Boltzmann distribution. 
C) fails to incorporate the exclusion principle. 
D) assumes the applicability of the equipartition theorem. 
E) incorporates all of these.

Question 12

The Madelung constant is given by the infinite sum $\alpha$ = 6 - 12/21/2 + 8/31/2 - ....Which of the following statements is true?

Accepted Answer

A) The numerators in these terms are the number of nearest neighbors in the crystal. 
B) The denominators in these terms are related to the distances to the nearest neighbors. 
C) The Madelung constant is the constant of proportionality in the expression for the net attractive potential energy of an ion in a crystal. 
D) The value of $\alpha$ depends on the geometry of the crystal. 
E) All of these are correct. 
A) The numerators in these terms are the number of nearest neighbors in the crystal. 
B) The denominators in these terms are related to the distances to the nearest neighbors. 
C) The Madelung constant is the constant of proportionality in the expression for the net attractive potential energy of an ion in a crystal. 
D) The value of $\alpha$ depends on the geometry of the crystal. 
E) All of these are correct.

Question 13

The equilibrium spacing r0 for NaCl is 0.282 nm and the mass of 1 mol of NaCl is 58.4 g.The density of NaCl must be

Accepted Answer

A) 10.2 g/cm3  
B) 6.35 g/cm3  
C) 3.68 g/cm3  
D) 2.16 g/cm3  
E) 1.08 g/cm3  
A) 10.2 g/cm3  
B) 6.35 g/cm3  
C) 3.68 g/cm3  
D) 2.16 g/cm3  
E) 1.08 g/cm3

Question 14

You place sodium and copper in contact.The contact potential you would expect to measure is

Accepted Answer

A) 4.1 V 
B) 2.3 V 
C) 1.8 V 
D) 1.13 $\times$ 1019 V 
E) 6.4 V 
A) 4.1 V 
B) 2.3 V 
C) 1.8 V 
D) 1.13 $\times$ 1019 V 
E) 6.4 V

Question 15

Use the following to answer the question below: 
 
-The probability that an energy state in copper 0.2 eV above the Fermi energy is occupied at T = 300 K is

Accepted Answer

A) 0.0365% 
B) 0.0404% 
C) 0.0438% 
D) 0.0457% 
E) 0.0496% 
A) 0.0365% 
B) 0.0404% 
C) 0.0438% 
D) 0.0457% 
E) 0.0496%

Question 16

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

Accepted Answer

A) 1.26% 
B) 2.52% 
C) 3.78% 
D) 12.6% 
E) 14.5% 
A) 1.26% 
B) 2.52% 
C) 3.78% 
D) 12.6% 
E) 14.5%

Question 17

Use the following to answer the question.  
-The graph that represents the density of states g(E)in a Fermi gas is

Accepted Answer

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

Question 18

If you want to produce a crystal from a liquid,you

Accepted Answer

A) cool the liquid slowly so that the molecules gradually lose their kinetic energy and thus form a large number of stable 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 large number of stable 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 19

The classical microscopic model of electric conduction

Accepted Answer

A) successfully predicts Ohm's law. 
B) relates the resistivity of conductors to the mean speed and the mean free path of the free electrons within the conductor. 
C) fails to correctly predict the measured values of resistivity. 
D) fails to account for the distinction between insulators,semiconductors,and conductors. 
E) is described by all of these statements. 
A) successfully predicts Ohm's law. 
B) relates the resistivity of conductors to the mean speed and the mean free path of the free electrons within the conductor. 
C) fails to correctly predict the measured values of resistivity. 
D) fails to account for the distinction between insulators,semiconductors,and conductors. 
E) is described by all of these statements.

Question 20

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

Exam 38: Solids and the Theory of Conduction

The frequency of the current observed at a Josephson junction is 976 MHz.The voltage applied to the junction to produce this current was

Forward biasing of a pn junction

Insulators are poor conductors of electricity because

Use the following to answer the question. -The graph that represents the Fermi energy distribution function n(E)is

If the atoms are treated as solid spheres,the fraction of volume occupied by the atoms in a face-centered-cubic unit cell is

KF has a face-centered-cubic lattice structure and the equilibrium spacing between the K+ and F- ions is 0.269 nm.It has a dissociation energy of 498 kJ/mol.The constant n in the empirical potential energy,Urep = A/rn,is

The molecules in a solid

If you apply a voltage of 3 µV to a Josephson junction,you can expect to measure a frequency of

The free-electron model of metals gives a good account of electrical conduction if

The crystalline structure known as body-centered-cubic

The classical free-electron theory of metals is inadequate in that it

The Madelung constant is given by the infinite sum α\alphaα = 6 - 12/21/2 + 8/31/2 - ....Which of the following statements is true?

The equilibrium spacing r0 for NaCl is 0.282 nm and the mass of 1 mol of NaCl is 58.4 g.The density of NaCl must be

You place sodium and copper in contact.The contact potential you would expect to measure is

Use the following to answer the question below: -The probability that an energy state in copper 0.2 eV above the Fermi energy is occupied at T = 300 K is

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

Use the following to answer the question. -The graph that represents the density of states g(E)in a Fermi gas is

If you want to produce a crystal from a liquid,you

The classical microscopic model of electric conduction

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

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

KF has a face-centered-cubic lattice structure and the equilibrium spacing between the K⁺ and F^- ions is 0.269 nm.It has a dissociation energy of 498 kJ/mol.The constant n in the empirical potential energy,U_rep = A/rⁿ,is

The Madelung constant is given by the infinite sum $\alpha$ = 6 - 12/2^1/2 + 8/3^1/2 - ....Which of the following statements is true?

The equilibrium spacing r₀ for NaCl is 0.282 nm and the mass of 1 mol of NaCl is 58.4 g.The density of NaCl must be