Deck 9: The Atom

Question 1

The uncertainty principle is a fundamental part of

A) Newtonian mechanics.
B) quantum mechanics.
C) the quantum theory of light.
D) the Bohr theory of the hydrogen atom.

Answer 1

quantum mechanics.

Question 2

The speed of a photon

A) is less than the speed of light.
B) is equal to the speed of light.
C) is greater than the speed of light.
D) Any of these choices could be correct, depending on its frequency.

Answer 2

is equal to the speed of light.

Question 3

Matter waves are

A) associated with all particles.
B) never associated with stationary particles.
C) never associated with charged particles.
D) never associated with uncharged particles.

Answer 3

never associated with stationary particles.

Question 4

The speed of the wave packet that corresponds to a moving particle is

A) less than the speed of light.
B) equal to the speed of light.
C) greater than the speed of light.
D) Any of these choices could be correct, depending on the frequency.

Question 5

When light is directed at a metal surface, the emitted electrons

A) are called photons.
B) have random energies.
C) have energies that depend upon the intensity of the light.
D) have energies that depend upon the frequency of the light.

Question 6

The wider the wavepacket of a particle, the

A) longer its wavelength.
B) higher its speed.
C) more precisely its position can be determined.
D) more precisely its momentum can be determined.

Question 7

An electron and a gamma ray have the same wavelength.

A) The electron has less energy than the photon energy of the gamma ray.
B) The electron has the same energy as the photon energy of the gamma ray.
C) The electron has more energy than the photon energy of the gamma ray.
D) Any of these choices could be correct, depending on the wavelength.

Question 8

X-rays are

A) electromagnetic waves of very short wavelength.
B) electromagnetic waves of very long wavelength.
C) matter waves of very short wavelength.
D) matter waves of very long wavelength.

Question 9

A proton and an electron have the same de Broglie wavelength.

A) The electron has the higher speed.
B) The proton has the higher speed.
C) They have the same speed.
D) Any of the choices is true, depending on the wavelength.

Question 10

The wavelengths in the various spectral series of an element

A) are the same for all elements.
B) are random.
C) are different for each element.
D) are different in the emission and absorption spectra of an element.

Question 11

The photoelectric effect occurs only when the incident light has more than a certain minimum

A) frequency.
B) wavelength.
C) speed.
D) charge.

Question 12

If Planck's constant were smaller than it is,

A) moving bodies would have longer wavelengths.
B) moving bodies would have lower speeds.
C) the uncertainty principle would be less significant.
D) photons would have higher energies.

Question 13

The wave character of a moving golf ball is not observed because

A) the ball is uncharged.
B) the matter waves are moving too fast.
C) the frequency of the matter waves is too low.
D) the wavelength of the matter waves is too short.

Question 14

Which of the following cannot be explained by the quantum theory of light?

A) interference
B) blackbody radiation
C) the photoelectric effect
D) X-ray production

Question 15

In order to increase the rate at which photoelectrons are emitted by a surface on which light is directed, it is necessary to increase the

A) frequency of the light.
B) wavelength of the light.
C) intensity of the light.
D) speed of the light.

Question 16

Which of these statements is true for the radiation emitted by all objects?

A) Under the same circumstances, black objects emit the least radiation.
B) The higher an object's temperature, the longer the predominant wavelength of its radiation.
C) The higher an object's temperature, the more radiation it emits.
D) The higher an object's temperature, the higher the speed of the radiation it emits.

Question 17

Photons have

A) no charge.
B) charges smaller than ±e, like quarks.
C) charges of ±e.
D) charges whose magnitudes depends on their speeds.

Question 18

An increase in the voltage applied to an X-ray tube causes an increase in the X-rays'

A) wavelength.
B) speed.
C) energy.
D) number.

Question 19

The idea that light has both wave and particle properties is accepted because

A) theory and experiment agree.
B) it is in accord with common sense.
C) it was revealed to Einstein in a dream.
D) photons have actually been seen.

Question 20

According to the uncertainty principle, it is impossible to precisely determine

A) only the position of a particle.
B) only the momentum of a particle.
C) either the position or the momentum of a particle.
D) both the position and the momentum of a particle.

Question 21

Electrons

A) have no magnetic properties.
B) have the same magnetic behavior as particles of iron.
C) behave like tiny bar magnets of different strengths.
D) behave like tiny bar magnets of the same strength.

Question 22

The number of quantum numbers needed to describe the state of an atomic electron is

A) 1.
B) 2.
C) 3.
D) 4.

Question 23

An atom in an excited state usually emits a photon and falls to a state of lower energy m about

A) 10^-8 s.
B) 1 s.
C) 10 s.
D) 1 min.

Question 24

The energy difference between adjacent energy levels in a hydrogen atom

A) decreases with increasing quantum numbers.
B) increases with increasing quantum numbers.
C) is the same for all quantum numbers.
D) shows no regularities.

Question 25

The orbital of an electron in an atom is

A) the region around the nucleus in which it is most likely to be found.
B) the path it follows around the nucleus.
C) its de Broglie wave.
D) its angular momentum.

Question 26

Classical physics cannot account for why

A) atoms can contain electrons.
B) atomic electrons are in motion.
C) atoms can emit electromagnetic waves.
D) atoms can be stable.

Question 27

The number of quantum numbers needed to determine the size and shape of an atomic orbital is

A) 1.
B) 2.
C) 3.
D) 4.

Question 28

The sun's spectrum consists of a bright background crossed by dark lines. This suggests that the sun

A) is a hot object surrounded by a hot atmosphere.
B) is a hot object surrounded by a cool temperature.
C) is a cool object surrounded by a hot temperature.
D) is a cool object surrounded by a cool atmosphere.

Question 29

The number of values the spin magnetic quantum number m_s of an atomic electron can have is

A) 1.
B) 2.
C) always equal to n, the principal quantum number.
D) always equal to 2n.

Question 30

A photon is emitted by an atom when one of the atom's electrons

A) leaves the atom.
B) collides with another of its electrons.
C) shifts to a lower energy level.
D) shifts to a higher energy level.

Question 31

The light waves from a laser

A) have different wavelengths.
B) have different speeds.
C) are in step with one another.
D) spread out to form a wide beam.

Question 32

The quantum number n of the lowest energy state of a hydrogen atom

A) is 0.
B) is 1.
C) depends on the orbit size.
D) depends on the electron speed.

Question 33

The fact that no two electrons in an atom can have the same set of quantum numbers is known as the

A) Bohr principle.
B) de Broglie principle.
C) exclusion principle.
D) uncertainty principle.

Question 34

A beam of light whose waves are all in step with one another is said to be

A) coherent.
B) incoherent.
C) quantized.
D) diffracted.

Question 35

An electron in an s state of an atom has an angular momentum quantum number of

A) 0.
B) 1.
C) 2.
D) 3.

Question 36

When a hydrogen atom is in its lowest energy level,

A) the de Broglie wavelength of its electron equals its orbit diameter.
B) the de Broglie wavelength of its electron equals its orbit circumference.
C) its electron has left the atom.
D) its electron is at rest.

Question 37

In an emission spectral series, the

A) lines are evenly spaced.
B) excited electrons all started from the same energy level.
C) excited electrons all return to the same energy level.
D) excited electrons leave the atoms.

Question 38

Each orbital in an atom can be occupied by

A) only one electron.
B) two electrons with spins in the same direction.
C) two electrons with spins in opposite directions.
D) any number of electrons.

Question 39

A neon sign does not produce

A) a line spectrum.
B) an emission spectrum.
C) an absorption spectrum.
D) photons.

Question 40

The electron structures of atoms never emit

A) gamma rays.
B) x-rays.
C) ultraviolet light.
D) infrared light.

Question 41

Planck's constant is h = 6.6 × 10^-34 Js and the electron mass is 9.1 × 10^-31 kg. The speed of an electron whose de Broglie wavelength is 10^-10 is

A) 6.6 × 10^-24 m/s.
B) 3.8 × 10³ m/s.
C) 7.3 × 10⁶ m/s.
D) 10¹⁰ m/s.

Question 42

A p orbital

A) is spherical in shape.
B) is shaped like a doughnut.
C) has two lobes.
D) has six lobes.

Question 43

Planck's constant is h = 6.6 × 10^-34 Js and the electron mass is 9.1 × 10^-31 kg. The de Broglie wavelength of an electron whose speed is 10⁸ m/s is

A) 5.9 × 10^-56 m.
B) 1.5 × 10^-19 m.
C) 7.3 × 10^-12 m.
D) 1.4 × 10¹¹ m.

Question 44

Planck's constant is h = 6.6 × 10^-34 Js. An x-ray photon has an energy of 6.6 × 10^-15 J. The frequency that corresponds to this energy is

A) 4.4 × 10^-48 Hz.
B) 10^-19 Hz.
C) 10¹⁵ Hz.
D) 10¹⁹ Hz.

Question 45

Planck's constant is h = 6.6 × 10^-34 Js. Light of wavelength 5 × 10^-7 m consists of photons whose energy is

A) 1.1 × 10^-48 J.
B) 1.3 × 10^-27 J.
C) 4 × 10^-19 J.
D) 1.7 × 10^-15 J.