Question 1

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 C

Question 2

In a laser:

Accepted Answer

A)  excited atoms are stimulated to emit photons by radiation external to the laser 
B)  the transitions for laser emission are directly to the ground state 
C)  the states which give rise to laser emission are usually very unstable states that decay rapidly 
D)  the state in which an atom is initially excited is never between two states that are involved in the stimulated emission 
E)  a minimum of two energy levels are required. 
A)  excited atoms are stimulated to emit photons by radiation external to the laser 
B)  the transitions for laser emission are directly to the ground state 
C)  the states which give rise to laser emission are usually very unstable states that decay rapidly 
D)  the state in which an atom is initially excited is never between two states that are involved in the stimulated emission 
E)  a minimum of two energy levels are required. D

Question 3

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. The number of single-particle states with energy 5(h2/8mL2) is:

Accepted Answer

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

Question 4

When a lithium atom in its ground state is made from a helium atom by adding a proton (and neutron) to the nucleus and an electron outside, the electron goes into an n = 2,   state rather than an n = 3,   This is an indication that electrons:

Accepted Answer

A)  obey the Pauli exclusion principle 
B)  obey the minimum energy principle 
C)  undergo the Zeeman effect 
D)  are diffracted 
E)  and protons are interchangeable 
A)  obey the Pauli exclusion principle 
B)  obey the minimum energy principle 
C)  undergo the Zeeman effect 
D)  are diffracted 
E)  and protons are interchangeable

Question 5

A photon with the smallest wavelength in the continuous z-ray spectrum is emitted when:

Accepted Answer

A)  an electron is knocked from a K shell 
B)  a valence electron is knocked from the atom 
C)  the incident electron becomes bound to the atom 
D)  the atom has the greatest recoil energy 
E)  the incident electron loses all its energy in a single decelerating event 
A)  an electron is knocked from a K shell 
B)  a valence electron is knocked from the atom 
C)  the incident electron becomes bound to the atom 
D)  the atom has the greatest recoil energy 
E)  the incident electron loses all its energy in a single decelerating event

Question 6

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

Accepted Answer

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

Question 7

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 8

The force exerted on a magnetic dipole as it moves with velocity   through a Stern-Gerlach apparatus is:

Accepted Answer

A)  proportional to v 
B)  proportional to 1/v 
C)  zero 
D)  proportional to v2 
E)  independent of v 
A)  proportional to v 
B)  proportional to 1/v 
C)  zero 
D)  proportional to v2 
E)  independent of v

Question 9

The magnetic field   is along the z axis in a Stern-Gerlach experiment. The force it exerts on a magnetic dipole with dipole moment   is proportional to:

Accepted Answer

A)    
B)  B2 
C)  dB/dz 
D)  d2B/dz2 
E) $\int$B dz 
A)    
B)  B2 
C)  dB/dz 
D)  d2B/dz2 
E) $\int$B dz

Question 10

Characteristic K x-radiation of an element is caused by:

Accepted Answer

A)  stoppage of electrons by the nucleus 
B)  scattering of the incident radiation with a change of wavelength 
C)  ejection of an electron from an outer shell 
D)  transition of an electron to the innermost orbit 
E)  none of the above 
A)  stoppage of electrons by the nucleus 
B)  scattering of the incident radiation with a change of wavelength 
C)  ejection of an electron from an outer shell 
D)  transition of an electron to the innermost orbit 
E)  none of the above

Question 11

The "e" in laser stands for:

Accepted Answer

A)  electric 
B)  emf 
C)  energy 
D)  emission 
E)  entropy 
A)  electric 
B)  emf 
C)  energy 
D)  emission 
E)  entropy

Question 12

The effective charge acting on a single valence electron outside a closed shell is about Ne, where N is:

Accepted Answer

A)  the atomic number of the nucleus 
B)  the atomic mass of the atom 
C)  usually between 1 and 3 
D)  half the atomic number 
E)  less than 1 
A)  the atomic number of the nucleus 
B)  the atomic mass of the atom 
C)  usually between 1 and 3 
D)  half the atomic number 
E)  less than 1

Question 13

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 14

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 15

The magnetic quantum number    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 16

The number of possible values of the magnetic quantum number   associated with a given value of the orbital quantum number   is:

Accepted Answer

A)  1 
B)  2 
C)    
D)    
E)    
A)  1 
B)  2 
C)    
D)    
E)

Question 17

Two different electron beams are incident on two different targets and both produce x rays. The cutoff wavelength for target 1 is shorter than the cutoff wavelength for target 2. We can conclude that:

Accepted Answer

A)  target 2 has a higher atomic number than target 1 
B)  target 2 has a lower atomic number than target 1 
C)  the electrons in beam 1 have greater kinetic energy than those in beam 2 
D)  the electrons in beam 1 have less kinetic energy than those in beam 2 
E)  target 1 is thicker than target 2 
A)  target 2 has a higher atomic number than target 1 
B)  target 2 has a lower atomic number than target 1 
C)  the electrons in beam 1 have greater kinetic energy than those in beam 2 
D)  the electrons in beam 1 have less kinetic energy than those in beam 2 
E)  target 1 is thicker than target 2

Question 18

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

Accepted Answer

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

Question 19

An electron in a K 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 20

The K $\infty$  x rays arixing from a cobalt (Z = 27) target have a wavelength of about 179 pm. The atomic number of a target that gives rise to K $\infty$  x rays with a wavelength one-third as great ($\approx$ 60pm) is:

Accepted Answer

A)  Z = 9 
B)  Z = 10 
C)  Z = 12 
D)  Z = 16 
E)  Z = 46 
A)  Z = 9 
B)  Z = 10 
C)  Z = 12 
D)  Z = 16 
E)  Z = 46

Exam 40: All About Atoms

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

In a laser:

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. The number of single-particle states with energy 5(h2/8mL2) is:

When a lithium atom in its ground state is made from a helium atom by adding a proton (and neutron) to the nucleus and an electron outside, the electron goes into an n = 2, state rather than an n = 3, This is an indication that electrons:

A photon with the smallest wavelength in the continuous z-ray spectrum is emitted when:

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

A laser must be pumped to achieve:

The force exerted on a magnetic dipole as it moves with velocity through a Stern-Gerlach apparatus is:

The magnetic field is along the z axis in a Stern-Gerlach experiment. The force it exerts on a magnetic dipole with dipole moment is proportional to:

Characteristic K x-radiation of an element is caused by:

The "e" in laser stands for:

The effective charge acting on a single valence electron outside a closed shell is about Ne, where N is:

The Pauli exclusion principle is obeyed by:

Which of the following subshells cannot exist?

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

The number of possible values of the magnetic quantum number associated with a given value of the orbital quantum number is:

Two different electron beams are incident on two different targets and both produce x rays. The cutoff wavelength for target 1 is shorter than the cutoff wavelength for target 2. We can conclude that:

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

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

The K ∞\infty∞ x rays arixing from a cobalt (Z = 27) target have a wavelength of about 179 pm. The atomic number of a target that gives rise to K ∞\infty∞ x rays with a wavelength one-third as great ( ≈\approx≈ 60pm) is:

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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. The number of single-particle states with energy 5(h²/8mL²) is:

The K _$\infty$ x rays arixing from a cobalt (Z = 27) target have a wavelength of about 179 pm. The atomic number of a target that gives rise to K _$\infty$ x rays with a wavelength one-third as great ( $\approx$ 60pm) is: