All About Atoms Chapter 40 11th Edition Verified Test Bank

Chapter: Chapter 40

Learning Objectives

LO 40.1.0 Solve problems related to properties of atoms.

LO 40.1.1 Discuss the pattern that is seen in a plot of ionization energies versus atomic number Z.

LO 40.1.2 Identify that atoms emit and absorb light and have angular momentum and magnetism

LO 40.1.3 Explain the Einstein–de Haas experiment, including the principle of the conservation of angular momentum.

LO 40.1.4 Identify the five quantum numbers of an electron in an atom and the allowed values of each.

LO 40.1.5 Determine the number of electron states allowed in a given shell and subshell.

LO 40.1.6 Identify that an electron in an atom has an orbital angular momentum and an orbital magnetic dipole moment .

LO 40.1.7 Calculate magnitudes for orbital angular momentum and orbital magnetic dipole moment in terms of the orbital quantum number ℓ.

LO 40.1.8 Apply the relationship between orbital angular momentum and orbital magnetic dipole moment .

LO 40.1.9 Identity that and cannot be observed (measured) but a component on a measurement axis (usually called the z axis) can.

LO 40.1.10 Calculate the z components L_z of an orbital angular momentum using the orbital magnetic quantum number m_ℓ.

LO 40.1.11 Calculate the z components μ_orb,z of an orbital magnetic dipole moment using the orbital magnetic quantum number m_ℓ and the Bohr magneton μ_B.

LO 40.1.12 For a given orbital state or spin state, calculate the semiclassical angle θ.

LO 40.1.13 Identify that a spin angular momentum (usually simply called spin) and a spin magnetic dipole moment are intrinsic properties of electrons (and also protons and neutrons).

LO 40.1.14 Calculate magnitudes for spin angular momentum and spin magnetic dipole moment in terms of the spin quantum number s.

LO 40.1.15 Apply the relationship between the spin angular momentum and the spin magnetic dipole moment .

LO 40.1.16 Identity that and cannot be observed (measured) but a component on a measurement axis can.

LO 40.1.17 Calculate the z components S_z of the spin angular momentum using the spin magnetic quantum number m_s.

LO 40.1.18 Calculate the z components μ_s,z of the spin magnetic dipole moment using the spin magnetic quantum number m_s and the Bohr magneton μ_B.

LO 40.1.19 Identify the effective magnetic dipole moment of an atom.

LO 40.2.0 Solve problems related to the Stern–Gerlach experiment.

LO 40.2.1 Sketch the Stern–Gerlach experiment and explain the type of atom required, the anticipated result, the actual result, and the importance of the experiment.

LO 40.2.2 Apply the relationship between the magnetic field gradient and the force on an atom in a Stern–Gerlach experiment.

LO 40.3.0 Solve problems related to magnetic resonance.

LO 40.3.1 For a proton in a magnetic field, sketch the field vector and the proton’s magnetic moment vector for the lower energy state and the upper energy state and then include the labels of spin up and spin down.

LO 40.3.2 For a proton in a magnetic field, calculate the energy difference between the two spin states and find the photon frequency and wavelength required for a transition between the states.

LO 40.3.3 Explain the procedure of producing a nuclear magnetic resonance spectrum.

LO 40.4.0 Solve problems related to the exclusion principle and multiple electrons in a trap.

LO 40.4.1 Identify the Pauli exclusion principle.

LO 40.4.2 Explain the procedure for placing multiple electrons in traps of one, two, and three dimensions, including the need to obey the exclusion principle and to allow for degenerate states, and explain the terms empty, partially occupied, and fully occupied.

LO 40.4.3 For a system of multiple electrons in traps of one, two, and three dimensions, produce energy-level diagrams.

LO 40.5.0 Solve problems related to building the periodic table.

LO 40.5.1 Identify that all states in a subshell have the same energy that is determined primarily by quantum number n but to a lesser extent by quantum number ℓ.

LO 40.5.2 Identify the labeling system for the orbital angular momentum quantum number.

LO 40.5.3 Identify the procedure for filling up the shells and subshells in building up the periodic table for as long as the electron-electron interaction can be neglected.

LO 40.5.4 Distinguish the noble gases from the other elements in terms of chemical interactions, net angular momentum, and ionization energy.

LO 40.5.5 For a transition between two given atomic energy levels, for either emission or absorption of light, apply the relationship between the energy difference and the frequency and wavelength of the light.

LO 40.6.0 Solve problems related to X rays and the ordering of the elements.

LO 40.6.1 Identify where x rays are located in the electromagnetic spectrum.

LO 40.6.2 Explain how x rays are produced in a laboratory or medical setting.

LO 40.6.3 Distinguish between a continuous x-ray spectrum and a characteristic x-ray spectrum.

LO 40.6.4 In a continuous x-ray spectrum, identify the cause of the cutoff wavelength λ_min.

LO 40.6.5 Identify that in an electron–atom collision, energy and momentum are conserved.

LO 40.6.6 Apply the relationship between a cutoff wavelength λ_min and the kinetic energy K₀ of the incident electrons.

LO 40.6.7 Draw an energy-level diagram for holes and identify (with labels) the transitions that produce x rays.

LO 40.6.8 For a given hole transition, calculate the wavelength of the emitted x ray.

LO 40.6.9 Explain the importance of Moseley’s work with regard to the periodic table.

LO 40.6.10 Sketch a Moseley plot.

LO 40.6.11 Describe the screening effect in a multielectron atom.

LO 40.6.12 Apply the relationship between the frequency of the emitted K-alpha x rays and the atomic number Z of the atoms.

LO 40.7.0 Solve problems related to lasers.

LO 40.7.1 Distinguish the light of a laser from the light of a common light bulb.

LO 40.7.2 Sketch energy-level diagrams for the three basic ways that light can interact with matter (atoms) and identify which is the basis of lasing.

LO 40.7.3 Identify metastable states.

LO 40.7.4 For two energy states, apply the relationship between the relative number of atoms in the higher state due to thermal agitation, the energy difference, and the temperature.

LO 40.7.5 Identify population inversion, explain why it is required in a laser, and relate it to the lifetimes of the states.

LO 40.7.6 Discuss how a helium–neon laser works, pointing out which gas lases and explaining why the other gas is required.

LO 40.7.7 For stimulated emission, apply the relationships between energy change, frequency, and wavelength.

LO 40.7.8 For stimulated emission, apply the relationships between energy, power, time, intensity, area, photon energy, and rate of photon emission.

Multiple Choice

1. The Einstein–de Haas experiment showed that:

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.

Difficulty: E

Section: 40-1

Learning Objective 40.1.3

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

A) 1

B) 1/2

C)

D) 2ℓ+1

E) ℓ²

Difficulty: E

Section: 40-1

Learning Objective 40.1.4

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

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

Difficulty: E

Section: 40-1

Learning Objective 40.1.4

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

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

Difficulty: E

Section: 40-1

Learning Objective 40.1.4

5. Possible values of the principal quantum number n for an electron in an atom are:

A) only 0 and 1

B) only 0,1,2,..., 

C) only 0,1,..., ℓ−1

D) only 1/2 and –1/2

E) only 1,2,3,..., 

Difficulty: E

Section: 40-1

Learning Objective 40.1.4

6. The number of values of the orbital quantum number ℓ associated with the principal quantum number n = 3 is:

A) 1

B) 2

C) 3

D) 4

E) 7

Difficulty: E

Section: 40-1

Learning Objective 40.1.4

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

A) 1

B) 2

C) ℓ

D) 2 ℓ

E) 2 ℓ +1

Difficulty: E

Section: 40-1

Learning Objective 40.1.4

8. An atom is in a state with orbital quantum number ℓ=2. Possible values of the magnetic quantum number m_ℓ are:

A) 1, 2

B) 0, 1, 2

C) 0, 1

D) –1, 0, 1

E) –2, –1, 0, 1, 2

Difficulty: E

Section: 40-1

Learning Objective 40.1.4

9. 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?

A) 7

B) 8

C) 16

D) 17

E) 20

Difficulty: M

Section: 40-1

Learning Objective 40.1.4

10. An electron in an atom is in a state with principal quantum number n = 4. The possible values of the orbital quantum number ℓ are:

A) 1, 2, 3

B) 1, 2, 3, 4

C) –3, –2, –1, 0, 1, 2, 3

D) 0, 1, 2, 3

E) 0, 1, 2

Difficulty: E

Section: 40-1

Learning Objective 40.1.4

11. The possible values for the magnetic quantum number m_s of an electron in an atom:

A) depend on n

B) depend on ℓ

C) depend on both n and ℓ

D) depend on whether or not there is an external magnetic field present

E) are 1/2

Difficulty: E

Section: 40-1

Learning Objective 40.1.4

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

A) 2

B) 3

C) 7

D) 9

E) 14

Difficulty: E

Section: 40-1

Learning Objective 40.1.5

13. The number of states in a shell with principal quantum number n = 3 is:

A) 3

B) 8

C) 9

D) 18

E) 32

Difficulty: M

Section: 40-1

Learning Objective 40.1.5

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

A) the same value of n

B) the same value of ℓ

C) the same value of n and the same value of ℓ

D) the same value of ℓ and the same value of m_ℓ

E) the same set of all four quantum numbers

Difficulty: E

Section: 40-1

Learning Objective 40.1.5

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

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 m_ℓ

E) the same set of all four quantum numbers

Difficulty: E

Section: 40-1

Learning Objective 40.1.5

16. The total number of electron states with n = 2 and ℓ=1 for an atom is:

A) 2

B) 4

C) 6

D) 8

E) 10

Difficulty: E

Section: 40-1

Learning Objective 40.1.5

17. An electron is in a quantum state for which there are seven allowed values of the z component of the angular momentum. The magnitude of the angular momentum is:

A)

B)

C)

D)

E)

Difficulty: M

Section: 40-1

Learning Objective 40.1.7

18. The magnitude of the orbital magnetic dipole moment of an atom is (_B is the Bohr magneton, and ℓ is a positive integer):

A) _B

B) _B ℓ

C) _B

D) _B (2ℓ+1)

E) _B ℓ²

Difficulty: E

Section: 40-1

Learning Objective 40.1.8

19. Space quantization means that:

A) space is quantized

B) L_z can have only certain discrete values

C) and are in the same direction

D) and are in opposite directions

E) an electron has a magnetic dipole moment

Difficulty: E

Section: 40-1

Learning Objective 40.1.9

20. The quantity L_z is related to the quantum number m_ℓ by:

A) L_z = m_ℓ

B) L_z = m_ℓ

C) L_z = m_ℓ

D) L_z =

E) L_z =

Difficulty: E

Section: 40-1

Learning Objective 40.1.10

21. In the relation µ_z=−m_ℓµ_B, the quantity _B is:

A) the Bohr magneton

B) the component of the dipole moment along the magnetic field

C) the permeability of the material

D) a friction coefficient

E) none of the above

Difficulty: E

Section: 40-1

Learning Objective 40.1.11

22. An electron in an atom is in a state with ℓ=3 and m_ℓ =2. The angle between and the z axis is:

A) 30

B) 35.3

C) 48.2

D) 54.7

E) 60

Difficulty: M

Section: 40-1

Learning Objective 40.1.12

23. An electron in an atom is in a state with ℓ=5. The minimum angle between and the z axis is:

A) 0

B) 18.0

C) 24.1

D) 33.6

E) 36.7

Difficulty: M

Section: 40-1

Learning Objective 40.1.12

24. The magnitude of the spin magnetic dipole moment of an atom is (_B is the Bohr magneton, and s is a positive number):

A) _B

B) _B s

C) _B

D) 2_B

E) 2_B s

Difficulty: M

Section: 40-1

Learning Objective 40.1.14

25. The quantity s_z is related to the quantum number m_s by:

A) s_z = m_s

B) s_z = m_s

C) s_z = m_s

D) s_z =

E) s_z =

Difficulty: E

Section: 40-1

Learning Objective 40.1.17

26. The Stern-Gerlach experiment makes use of:

A) a strong uniform magnetic field

B) a strong non-uniform magnetic field

C) a strong uniform electric field

D) a strong non-uniform electric field

E) strong perpendicular electric and magnetic fields

Difficulty: E

Section: 40-2

Learning Objective 40.2.0

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

A) along

B) along

C) along

D) along

E) zero

Difficulty: E

Section: 40-2

Learning Objective 40.2.0

28. 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:

A)

B) B²

C) dB/dz

D) d²B/dz²

E) B dz

Difficulty: E

Section: 40-2

Learning Objective 40.2.2

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

A) proportional to v

B) proportional to 1/v

C) zero

D) proportional to v²

E) independent of v

Difficulty: E

Section: 40-2

Learning Objective 40.2.2

30. A magnetic dipole is placed between the poles of a magnet as shown. The direction of the associated force exerted on the dipole is:

A) positive x

B) positive y

C) negative x

D) negative y

E) into or out of the page

Difficulty: E

Section: 40-2

Learning Objective 40.2.2

31. The figure shows two different orientations of a proton in a magnetic field. Which orientation is at higher energy?

A) a

B) b

C) Both are at the same energy, and there is no other orientation at higher energy.

D) Both are at the same energy, but if the spin vector were perpendicular to the magnetic field the energy would be higher.

E) Both are at the same energy, but if the spin vector were perpendicular to the magnetic field the energy would be lower.

Difficulty: E

Section: 40-3

Learning Objective 40.3.1

32. Hydrogen atoms are in a magnetic field of 2.0 T. What is their magnetic resonance frequency?

A) 2.8 x 10¹⁰ Hz

B) 5.6 x 10¹⁰ Hz

C) 1.1 x 10¹¹ Hz

D) 1.8 x 10¹¹ Hz

E) 3.5 x 10¹¹ Hz

Difficulty: M

Section: 40-3

Learning Objective 40.3.2

33. The Pauli exclusion principle is obeyed by:

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

Difficulty: E

Section: 40-4

Learning Objective 40.4.1

34. No state in an atom can be occupied by more than one electron. This is most closely related to the:

A) wave nature of matter

B) finite value for the speed of light

C) Bohr magneton

D) Pauli exclusion principle

E) the Einstein-de Haas effect

Difficulty: E

Section: 40-4

Learning Objective 40.4.1

35. 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:

A) 1

B) 2

C) 3

D) 4

E) any number

Difficulty: M

Section: 40-4

Learning Objective 40.4.2

36. Five 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 energy of the ground state of the system is

A) 0

B) 10 (h²/8mL²)

C) 19 (h²/8mL²)

D) 24 (h²/8mL²)

E) 48 (h²/8mL²)

Difficulty: M

Section: 40-4

Learning Objective 40.4.2

37. Five 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 energy of the first excited state of the system is:

A) 13 (h²/8mL²)

B) 22 (h²/8mL²)

C) 24 (h²/8mL²)

D) 25 (h²/8mL²)

E) 27 (h²/8mL²)

Difficulty: M

Section: 40-4

Learning Objective 40.4.2

38. 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:

A) 1

B) 2

C) 3

D) 4

E) 5

Difficulty: M

Section: 40-4

Learning Objective 40.4.2

39. Six 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. If a seventh electron is added to the system when it is in its ground state the least energy the additional electron can have is:

A) 2 (h²/8mL²)

B) 5 (h²/8mL²)

C) 8 (h²/8mL²)

D) 10 (h²/8mL²)

E) 13 (h²/8mL²)

Difficulty: M

Section: 40-4

Learning Objective 40.4.3

40. When a lithium atom 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, ℓ=0 state rather than an n = 1, ℓ=0 state. This is an indication that electrons:

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

Difficulty: E

Section: 40-5

Learning Objective 40.5.0

41. The most energetic electron in any atom at the beginning of a period of the periodic table is in:

A) an ℓ=0 state

B) an ℓ=1 state

C) an ℓ=2 state

D) an n = 0 state with unspecified angular momentum

E) an n = 1 state with unspecified angular momentum

Difficulty: E

Section: 40-5

Learning Objective 40.5.0

42. The most energetic electron in any atom at the end of a period of the periodic table is in:

A) an ℓ=0 state

B) an ℓ=1 state

C) an ℓ=2 state

D) an n = 0 state with unspecified angular momentum

E) an n = 1 state with unspecified angular momentum

Difficulty: E

Section: 40-5

Learning Objective 40.5.0

43. The group of atoms at the ends of periods of the periodic table is called:

A) alkali metal atoms

B) rare earth atoms

C) transition metal atoms

D) alkaline atoms

E) noble gas atoms

Difficulty: E

Section: 40-5

Learning Objective 40.5.0

44. The group of atoms at the beginning of periods of the periodic table is called:

A) alkali metal atoms

B) rare earth atoms

C) transition metal atoms

D) alkaline atoms

E) noble gas atoms

Difficulty: E

Section: 40-5

Learning Objective 40.5.0

45. The ionization energy of an atom in its ground state is:

A) the energy required to remove the least energetic electron

B) the energy required to remove the most energetic electron

C) the energy difference between the most energetic electron and the least energetic electron

D) the same as the energy of a K_ photon

E) the same as the excitation energy of the most energetic electron

Difficulty: E

Section: 40-5

Learning Objective 40.5.0

46. Which of the following subshells cannot exist?

A) 3p

B) 2p

C) 4d

D) 3d

E) 2d

Difficulty: E

Section: 40-5

Learning Objective 40.5.2

47. If electrons did not have intrinsic angular momentum (spin) but still obeyed the Pauli exclusion principle the states occupied by electrons in the ground state of helium would be:

A) (n = 1, ℓ=0); (n = 1, ℓ=0)

B) (n = 1, ℓ=0); (n = 1, ℓ=1)

C) (n = 1, ℓ=0); (n = 2, ℓ=0)

D) (n = 2, ℓ=0); (n = 2, ℓ=1)

E) (n = 2, ℓ=1); (n = 2, ℓ=1)

Difficulty: M

Section: 40-5

Learning Objective 40.5.3

48. Which of the following (n, ℓ, m_ℓ, m_s) combinations is impossible for an electron in an atom?

A) 3, 1, 1, –1/2

B) 6, 2, 0, 1/2

C) 3, 2, –2, –1/2

D) 3, 1, –2, 1/2

E) 1, 0, 0, –1/2

Difficulty: E

Section: 40-5

Learning Objective 40.5.3

49. For any atom other that hydrogen and helium all electrons in the same shell have:

A) the same energy

B) the same magnitude of angular momentum

C) the same magnetic quantum number

D) the same spin quantum number

E) none of the above

Difficulty: E

Section: 40-5

Learning Objective 40.5.3

50. The states being filled from the beginning to end of the lanthanide series of atoms are:

A) n = 3, ℓ=2 states

B) n = 4, ℓ=1 states

C) n = 4, ℓ=2 states

D) n = 4, ℓ=3 states

E) n = 5, ℓ=2 states

Difficulty: E

Section: 40-5

Learning Objective 40.5.3

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

A) n = 0

B) n = 1

C) n = 2

D) n = 3

E) n = 

Difficulty: E

Section: 40-6

Learning Objective 40.6.0

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

A) n = 0

B) n = 1

C) n = 2

D) n = 3

E) n = 

Difficulty: E

Section: 40-6

Learning Objective 40.6.0

53. In connection with x-ray emission the symbol K_ refers to:

A) an alpha particle radiation

B) an effect of the dielectric constant on energy levels

C) x-ray radiation from potassium

D) x-ray radiation associated with an electron going from n =  to n = 1

E) x-ray radiation associated with an electron going from n = 2 to n = 1

Difficulty: E

Section: 40-6

Learning Objective 40.6.0

54. In connection with x-ray emission the symbol L_ refers to:

A) a beta particle radiation

B) an atomic state of angular momentum h/2

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

Difficulty: E

Section: 40-6

Learning Objective 40.6.0

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

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

Difficulty: E

Section: 40-6

Learning Objective 40.6.2

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

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

Difficulty: E

Section: 40-6

Learning Objective 40.6.4

57. 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) 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

Difficulty: E

Section: 40-6

Learning Objective 40.6.4

58. 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:

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

Difficulty: M

Section: 40-6

Learning Objective 40.6.6

59. The transition shown gives rise to an x-ray. The correct label for this is:

A) K_

B) K_

C) L_

D) L_

E) KL

Difficulty: E

Section: 40-6

Learning Objective 40.6.7

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

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

Difficulty: E

Section: 40-6

Learning Objective 40.6.8

61. In a Moseley graph:

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

Difficulty: E

Section: 40-6

Learning Objective 40.6.10

62. 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:

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

Difficulty: E

Section: 40-6

Learning Objective 40.6.11

63. The K_ x rays arising from a cobalt (Z = 27) target have a wavelength of about 179 pm. The atomic number of a target that gives rise to K_ x rays with a wavelength one-third as great (60pm) is:

A) Z = 9

B) Z = 26

C) Z = 28

D) Z = 46

E) Z = 81

Difficulty: M

Section: 40-6

Learning Objective 40.6.12

64. The ratio of wavelength of K_ x-ray line for Nb (Z = 41) to that of Ga (Z = 31) is:

A) 9/16

B) 16/9

C) 3/4

D) 4/3

E) 1.15

Difficulty: M

Section: 40-6

Learning Objective 40.6.12

65. In a laser:

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.

Difficulty: E

Section: 40-7

Learning Objective 40.7.0

66. A laser beam can be sharply focused because it is:

A) highly coherent

B) plane polarized

C) intense

D) circularly polarized

E) highly directional

Difficulty: E

Section: 40-7

Learning Objective 40.7.0

67. The "e" in laser stands for:

A) electric

B) emf

C) energy

D) emission

E) entropy

Difficulty: E

Section: 40-7

Learning Objective 40.7.0

68. Photons in a laser beam have the same energy, wavelength, polarization direction, and phase because:

A) each is produced in an emission that is stimulated by another

B) all come from the same atom

C) the lasing material has only two quantum states

D) all photons are alike, no matter what their source

E) none of the above

Difficulty: E

Section: 40-7

Learning Objective 40.7.1

69. A group of electromagnetic waves might

Which of these describe the waves from a laser?

A) I only

B) II only

C) III only

D) I and II only

E) I, II, and III

Difficulty: E

Section: 40-7

Learning Objective 40.7.1

70. Suppose the energy required to ionize a neon atom is i, the energy to excite it is e, and its energy due to thermal agitation at room temperature is t. In increasing order, these three energies are:

A) i, e, t

B) t, i, e

C) e, t, i

D) i, t, e

E) t, e, i

Difficulty: E

Section: 40-7

Learning Objective 40.7.4

71. A laser must be pumped to achieve:

A) a metastable state

B) fast response

C) stimulated emission

D) population inversion

E) the same wavelength for all photons

Difficulty: E

Section: 40-7

Learning Objective 40.7.5

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

A) the lower level is metastable

B) the upper level is metastable

C) the lower level is the ground state

D) the are more atoms in the lower level than in the upper level

E) the lasing material is a gas

Difficulty: E

Section: 40-7

Learning Objective 40.7.5

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

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

Difficulty: E

Section: 40-7

Learning Objective 40.7.5

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

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

Difficulty: E

Section: 40-7

Learning Objective 40.7.5

75. A metastable state is important for the generation of a laser beam because it assures that:

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

Difficulty: E

Section: 40-7

Learning Objective 40.7.5

76. Photons in a laser beam are produced by:

A) transitions from a metastable state

B) transitions from a state that decays rapidly

C) splitting of other photons

D) pumping

E) reflection from mirrors

Difficulty: E

Section: 40-7

Learning Objective 40.7.6

77. In a helium-neon laser, the laser light arises from a transition from a _________ state to a _________ state:

A) He, He

B) Ne, Ne

C) He, Ne

D) Ne, He

E) N, He

Difficulty: E

Section: 40-7

Learning Objective 40.7.6

78. The purpose of the mirrors at the ends of a helium-neon laser is:

A) to assure that no laser light leaks out

B) to increase the number of stimulated emissions

C) to absorb some of the photons

D) to keep the light used for pumping inside the laser

E) to double the effective length of the laser

Difficulty: E

Section: 40-7

Learning Objective 40.7.6

79. Electrons in a certain laser make transitions from a metastable state to the ground state. Initially there are 6  10²⁰ atoms in the metastable state and 2  10²⁰ atoms in the ground state. The number of photons that can be produced in a single burst is about:

A) 2  10²⁰

B) 3  10²⁰

C) 4  10²⁰

D) 6  10²⁰

E) 8  10²⁰

Difficulty: E

Section: 40-7

Learning Objective 40.7.8