Question 1

A magnetic dipole   is placed in a strong uniform magnetic field   The associated force e exerted on the dipole is:

Accepted Answer

A)    
B)    
C)  along   
D)  along   
E)  zero 
A)    
B)    
C)  along   
D)  along   
E)  zero

Question 2

The magnitude of the orbital angular momentum of an electron is what multiple of ? (ℓ is a positive integer.)

Accepted Answer

A)  1 
B)  1/2 
C)    
D)  2ℓ+1 
E)  ℓ2 
A)  1 
B)  1/2 
C)    
D)  2ℓ+1 
E)  ℓ2

Question 3

The Einstein-de Haas experiment showed that:

Accepted Answer

A)  atoms emit and absorb light, but only of certain wavelengths. 
B)  atoms have momentum, and momentum is conserved. 
C)  atoms have electric fields, and electric fields can cause their energy levels to split. 
D)  atoms have magnetic dipole moments that are coupled to their angular momentum. 
E)  a gradient in a magnetic field will cause a beam of atoms to split. 
A)  atoms emit and absorb light, but only of certain wavelengths. 
B)  atoms have momentum, and momentum is conserved. 
C)  atoms have electric fields, and electric fields can cause their energy levels to split. 
D)  atoms have magnetic dipole moments that are coupled to their angular momentum. 
E)  a gradient in a magnetic field will cause a beam of atoms to split.

Question 4

Population inversion is important for the generation of a laser beam because it assures that:

Accepted Answer

A)  spontaneous emission does not occur more often than stimulated emission 
B)  photons do not split too rapidly 
C)  more photons are emitted than are absorbed 
D)  photons do not collide with each other 
E)  photons do not make upward transitions 
A)  spontaneous emission does not occur more often than stimulated emission 
B)  photons do not split too rapidly 
C)  more photons are emitted than are absorbed 
D)  photons do not collide with each other 
E)  photons do not make upward transitions

Question 5

The Pauli exclusion principle is obeyed by:

Accepted Answer

A)  all particles 
B)  all charged particles 
C)  all particles with spin quantum numbers of 1/2 
D)  all particles with spin quantum numbers of 1 
E)  all particles with mass 
A)  all particles 
B)  all charged particles 
C)  all particles with spin quantum numbers of 1/2 
D)  all particles with spin quantum numbers of 1 
E)  all particles with mass

Question 6

In a Moseley graph:

Accepted Answer

A)  the x-ray frequency is plotted as a function of atomic number 
B)  the square of the x-ray frequency is plotted as a function of atomic number 
C)  the square root of the x-ray frequency is plotted as a function of atomic number 
D)  the x-ray frequency is plotted as a function of the square root of atomic number 
E)  the square root of the x-ray frequency is plotted as a function of atomic mass 
A)  the x-ray frequency is plotted as a function of atomic number 
B)  the square of the x-ray frequency is plotted as a function of atomic number 
C)  the square root of the x-ray frequency is plotted as a function of atomic number 
D)  the x-ray frequency is plotted as a function of the square root of atomic number 
E)  the square root of the x-ray frequency is plotted as a function of atomic mass

Question 7

The number of states in a subshell with orbital quantum number ℓ=3 is:

Accepted Answer

A)  2 
B)  3 
C)  7 
D)  9 
E)  14 
A)  2 
B)  3 
C)  7 
D)  9 
E)  14

Question 8

Which of the following subshells cannot exist?

Accepted Answer

A)  3p 
B)  2p 
C)  4d 
D)  3d 
E)  2d 
A)  3p 
B)  2p 
C)  4d 
D)  3d 
E)  2d

Question 9

Which of the following is essential for the laser action to occur between two energy levels of an atom?

Accepted Answer

A)  the lower level is metastable 
B)  there are more atoms in the upper level than in the lower level 
C)  there are more atoms in the lower level than in the upper level 
D)  the lower level is the ground state 
E)  the lasing material is a gas 
A)  the lower level is metastable 
B)  there are more atoms in the upper level than in the lower level 
C)  there are more atoms in the lower level than in the upper level 
D)  the lower level is the ground state 
E)  the lasing material is a gas

Question 10

An electron is in a quantum state for which the magnitude of the orbital angular momentum is . How many allowed values of the z component of the angular momentum are there?

Accepted Answer

A)  7 
B)  8 
C)  16 
D)  17 
E)  20 
A)  7 
B)  8 
C)  16 
D)  17 
E)  20

Question 11

The quantum number ms is most closely associated with what property of the electron in an atom?

Accepted Answer

A)  Magnitude of the orbital angular momentum 
B)  Energy 
C)  z component of the spin angular momentum 
D)  z component of the orbital angular momentum 
E)  Radius of the orbit 
A)  Magnitude of the orbital angular momentum 
B)  Energy 
C)  z component of the spin angular momentum 
D)  z component of the orbital angular momentum 
E)  Radius of the orbit

Question 12

A laser must be pumped to achieve:

Accepted Answer

A)  a metastable state 
B)  fast response 
C)  stimulated emission 
D)  population inversion 
E)  the same wavelength for all photons 
A)  a metastable state 
B)  fast response 
C)  stimulated emission 
D)  population inversion 
E)  the same wavelength for all photons

Question 13

The electron states in an atom which constitute a single subshell all have:

Accepted Answer

A)  only the same value of n 
B)  only the same value of ℓ 
C)  only the same value of n and the same value of ℓ 
D)  only the same value of ℓ and the same value of mℓ 
E)  the same set of all four quantum numbers 
A)  only the same value of n 
B)  only the same value of ℓ 
C)  only the same value of n and the same value of ℓ 
D)  only the same value of ℓ and the same value of mℓ 
E)  the same set of all four quantum numbers

Question 14

Radiation with the minimum wavelength as well as the K x-ray lines are detected for a certain target. The energy of the incident electrons is then doubled, with the result that:

Accepted Answer

A)  the minimum wavelength increases and the wavelengths of the K lines remain the same 
B)  the minimum wavelength decreases and the wavelengths of the K lines remain the same 
C)  the minimum wavelength and the wavelengths of the K lines all increase 
D)  the minimum wavelength and the wavelengths of the K lines all decrease 
E)  the minimum wavelength increases and the wavelengths of the K lines all decrease 
A)  the minimum wavelength increases and the wavelengths of the K lines remain the same 
B)  the minimum wavelength decreases and the wavelengths of the K lines remain the same 
C)  the minimum wavelength and the wavelengths of the K lines all increase 
D)  the minimum wavelength and the wavelengths of the K lines all decrease 
E)  the minimum wavelength increases and the wavelengths of the K lines all decrease

Question 15

In calculating the x-ray energy levels the effective charge of the nucleus is taken to be Z - b, where Z is the atomic number. The parameter b enters because:

Accepted Answer

A)  an electron is removed from the inner shell 
B)  a proton is removed from the nucleus 
C)  the quantum mechanical force between two charges is less than the classical force 
D)  the nucleus is screened by electrons 
E)  the Pauli exclusion principle must be obeyed 
A)  an electron is removed from the inner shell 
B)  a proton is removed from the nucleus 
C)  the quantum mechanical force between two charges is less than the classical force 
D)  the nucleus is screened by electrons 
E)  the Pauli exclusion principle must be obeyed

Question 16

The most energetic photon in a continuous x-ray spectrum has an energy approximately equal to:

Accepted Answer

A)  the energy of all the electrons in a target atom 
B)  the kinetic energy of an incident-beam electron 
C)  the rest energy, mc2, of an electron 
D)  the total energy of a K-electron in the target atom 
E)  the kinetic energy of a K-electron in the target atom 
A)  the energy of all the electrons in a target atom 
B)  the kinetic energy of an incident-beam electron 
C)  the rest energy, mc2, of an electron 
D)  the total energy of a K-electron in the target atom 
E)  the kinetic energy of a K-electron in the target atom

Question 17

The quantity Lz is related to the quantum number mℓ by:

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 18

An electron in an L shell of an atom has the principal quantum number:

Accepted Answer

A)  n = 0 
B)  n = 1 
C)  n = 2 
D)  n = 3 
E)  n = $\infty$ 
A)  n = 0 
B)  n = 1 
C)  n = 2 
D)  n = 3 
E)  n = $\infty$

Question 19

In connection with x-ray emission the symbol L $\beta$  refers to:

Accepted Answer

A)  a beta particle radiation 
B)  an atomic state of angular momentum h/2 $\pi$ 
C)  the inductance associated with an orbiting electron 
D)  x-radiation associated with an electron going from n = 4 to n = 2 
E)  none of the above 
A)  a beta particle radiation 
B)  an atomic state of angular momentum h/2 $\pi$ 
C)  the inductance associated with an orbiting electron 
D)  x-radiation associated with an electron going from n = 4 to n = 2 
E)  none of the above

Question 20

Electrons are in a two-dimensional square potential energy well with sides of length L. The potential energy is infinite at the sides and zero inside. The single-particle energies are given by , , where nx and ny are integers. At most the number of electrons that can have energy 8(h2/8mL2) is:

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  any number 
A)  1 
B)  2 
C)  3 
D)  4 
E)  any number

Exam 40: All About Atoms

A magnetic dipole is placed in a strong uniform magnetic field The associated force e exerted on the dipole is:

The magnitude of the orbital angular momentum of an electron is what multiple of ? (ℓ is a positive integer.)

The Einstein-de Haas experiment showed that:

Population inversion is important for the generation of a laser beam because it assures that:

The Pauli exclusion principle is obeyed by:

In a Moseley graph:

The number of states in a subshell with orbital quantum number ℓ=3 is:

Which of the following subshells cannot exist?

Which of the following is essential for the laser action to occur between two energy levels of an atom?

An electron is in a quantum state for which the magnitude of the orbital angular momentum is . How many allowed values of the z component of the angular momentum are there?

The quantum number ms is most closely associated with what property of the electron in an atom?

A laser must be pumped to achieve:

The electron states in an atom which constitute a single subshell all have:

Radiation with the minimum wavelength as well as the K x-ray lines are detected for a certain target. The energy of the incident electrons is then doubled, with the result that:

In calculating the x-ray energy levels the effective charge of the nucleus is taken to be Z - b, where Z is the atomic number. The parameter b enters because:

The most energetic photon in a continuous x-ray spectrum has an energy approximately equal to:

The quantity Lz is related to the quantum number mℓ by:

An electron in an L shell of an atom has the principal quantum number:

In connection with x-ray emission the symbol L β\betaβ refers to:

Electrons are in a two-dimensional square potential energy well with sides of length L. The potential energy is infinite at the sides and zero inside. The single-particle energies are given by , , where nx and ny are integers. At most the number of electrons that can have energy 8(h2/8mL2) is:

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The quantum number m_s is most closely associated with what property of the electron in an atom?

The quantity L_z is related to the quantum number m_ℓby:

In connection with x-ray emission the symbol L _$\beta$ refers to:

Electrons are in a two-dimensional square potential energy well with sides of length L. The potential energy is infinite at the sides and zero inside. The single-particle energies are given by , , where n_x and n_y are integers. At most the number of electrons that can have energy 8(h²/8mL²) is: