Deck 31: Light Quanta

Question 1

The first to be credited with the idea that energy was quantized was

A)Max Planck.
B)Albert Einstein.
C)both Planck and Einstein at about the same time.

Answer 1

Max Planck.

Question 2

Applying E = hf to photon emission from an atom, the symbol E represents the energy

A)of the emitted photon.
B)difference between atomic energy levels producing the photon.
C)both of these
D)neither of these

Answer 2

both of these

Question 3

Two pulses of light, one red and one blue, have the same energy. The pulse with the greater number of photons is the

A)red pulse.
B)blue pulse.
C)both the same

Answer 3

red pulse.

Question 4

Which has more energy per photon?

A)red light
B)blue light
C)both the same

Question 5

In the equation E = hf, the symbol h stands for

A)half-life.
B)momentum as it pertains to light.
C)energy per photon wavelength.
D)none of the above

Question 6

Which of the following is quantized?

A)energy
B)radiation
C)number of atoms in a gold bar
D)electric charge
E)all of the above

Question 7

A quantum of light is called

A)a proton.
B)a neutron.
C)an electron.
D)a neutrino.
E)none of the above

Question 8

Hypothetically, if Planck's constant were smaller, atoms would be

A)larger.
B)smaller.
C)no different in physical size.

Question 9

The first to be credited with the idea that light is quantized was

A)Max Planck.
B)Albert Einstein.
C)both Planck and Einstein at about the same time.

Question 10

Which experiment best illustrates the particle-like nature of light?

A)photoelectric effect
B)double-slit experiment
C)both of these
D)neither of these

Question 11

The phenomenon easily explained only in terms of the particle model of light is

A)reflection.
B)refraction.
C)photoelectric effect.
D)diffraction.
E)none of the above

Question 12

In the photoelectric effect, the brighter the illuminating light on a photosensitive surface, the greater the

A)number of ejected electrons.
B)velocity of ejected electrons.
C)both of these
D)neither of these

Question 13

The photoelectric effect supports a

A)wave nature of light.
B)particle nature of light.
C)both of these
D)none of these

Question 14

A lump of energy associated with light is called a

A)quantum.
B)photon.
C)both of these
D)neither of these

Question 15

The ratio of the energy of a photon to its frequency is

A)?.
B)Planck's constant.
C)photon speed.
D)photon wavelength.
E)unknown.

Question 16

The photons having greatest energy are those of

A)infrared.
B)red light.
C)green light.
D)blue light.
E)ultraviolet.

Question 17

The photons having least energy are those of

A)infrared.
B)red light.
C)green light.
D)blue light.
E)ultraviolet.

Question 18

In the equation E = hf, the symbol E stands for

A)excitation.
B)efficiency.
C)energy.
D)all of the above

Question 19

The ratio of a photon's energy to its frequency is

A)its speed.
B)its wavelength.
C)its amplitude.
D)Planck's constant.
E)none of the above

Question 20

In the equation E = hf, the symbol f stands for

A)wave frequency.
B)wavelength.
C)rate at which photons are emitted.
D)none of the above

Question 21

In photoelectric emission, the work function is the minimum

A)frequency of light to produce emission.
B)energy required to eject an electron from the surface.
C)energy an emitted electron possesses.
D)none of the above

Question 22

Two photons that have the same wavelength also have the same

A)frequency.
B)energy.
C)both of these
D)neither of these

Question 23

If we increase the brightness of violet light shining on a photosensitive surface we also increases the

A)number of electrons ejected per second.
B)kinetic energy of the ejected electrons.
C)threshold frequency.
D)time lag between the absorption of blue light and ejection of electrons.
E)none of the above

Question 24

Light behaves primarily as a particle when it

A)travels from one place to another.
B)interacts with matter.
C)both of these
D)neither of these

Question 25

When ejected electrons from a photosensitive surface are confined within the material we have a

A)photovoltaic cell.
B)light-emitting diode.
C)both of these
D)none of these

Question 26

Light behaves primarily as a wave when it

A)travels from one place to another.
B)interacts with matter.
C)both of these
D)neither of these

Question 27

To study the energy of photoelectrons we measure

A)the potential difference required to stop them.
B)the distance traveled in a given time.
C)the time taken to travel a given distance.
D)their temperature.

Question 28

The physics underlying photovoltaic solar cells is

A)electron diffraction.
B)photon capture.
C)the photoelectric effect.
D)none of the above

Question 29

Taking the work function into account, electrons ejected from a photosensitive material have

A)less kinetic energy than the absorbed photon's energy.
B)more kinetic energy than the absorbed photon's energy.
C)kinetic energy equal to the absorbed photon's energy.

Question 30

After passing through double slits, electrons make a pattern on a screen that

A)shows which slit each electron has passed through.
B)resembles a pattern that waves make.
C)has two peaks of intensity.
D)has a single wide peak of intensity.

Question 31

According to Louis de Broglie, a material particle has

A)particle properties.
B)wave properties.
C)both of these
D)neither of these

Question 32

An electron microscope makes use of

A)short wavelengths of light.
B)the wave nature of electrons.
C)electron attraction and repulsion.
D)electron current.
E)the inertia of electrons.

Question 33

The wavelength of a particle relates to its

A)momentum.
B)energy levels.
C)quantum number.
D)all of the above
E)none of the above

Question 34

Which produces an interference pattern when directed through two suitably spaced slits?

A)light
B)sound
C)electrons
D)all of the above
E)none of the above

Question 35

The wave-particle duality applies to

A)photons.
B)electrons.
C)protons
D)all of the above
E)none of the above

Question 36

If a proton and an electron have the same momentum, the longer wavelength belongs to the

A)proton.
B)electron.
C)both the same

Question 37

Which can undergo diffraction?

A)photons.
B)electrons.
C)positrons.
D)all of the above
E)none of the above

Question 38

A photosensitive surface is illuminated with both blue and violet light. The light that causes the greater number of ejected electrons is

A)blue light.
B)violet light.
C)both eject equal numbers.
D)need more information

Question 39

Very low-intensity light passing through a double slit produces a pattern that

A)is built up one photon at a time.
B)reveals which slit each photon passed through.
C)changes only in intensity as time passes, not in detailed structure.

Question 40

The greater the frequency of the illuminating light on a photosensitive surface, the greater the

A)number of ejected electrons.
B)velocity of ejected electrons.
C)both of these
D)neither of these

Question 41

An electron and a baseball move at the same speed. Which has the longer wavelength?

A)the electron
B)the baseball
C)both the same
D)none of the above

Question 42

The Heisenberg uncertainty principle states that

A)Planck's constant sets a limit on accuracy of measurements.
B)we can't simultaneously measure exactly both the position and momentum of a particle.
C)we can't simultaneously measure exactly a particle's energy and time having that energy.
D)all of the above

Question 43

An electron and a proton are traveling at the same speed. Which has the longer wavelength?

A)the electron
B)the proton
C)both the same
D)none of the above

Question 44

Heisenberg's uncertainty principle is

A)noticeable only for submicroscopic particles.
B)a fundamental principle in quantum mechanics.
C)predominant in the atomic domain.
D)all of the above
E)none of the above

Question 45

By adjusting a TV image with a remote you can

A)affect only the image.
B)participate with the action on the screen.
C)both of these
D)neither of these

Question 46

When you adjust a telescope to get a clear image of Saturn's rings, there is a perceptible interaction between

A)you and the telescope.
B)you and Saturn's rings.
C)both of these
D)neither these

Question 47

By casually glancing at a scene on your TV you are

A)affecting the image.
B)participating in the action on the screen.
C)both of these
D)neither of these

Question 48

The formula △p △ x≥ h tells us that the product of △p and △x cannot be

A)less than h
B)greater than h
C)equal to h

Question 49

According to Heisenberg's uncertainty principle, the more we know about a particle's momentum, the less we know about its

A)kinetic energy.
B)mass.
C)speed.
D)location.
E)none of the above

Question 50

What is conserved when a photon collides with an electron?

A)momentum
B)energy
C)both of these
D)neither of these

Question 51

A bullet and a proton have the same momentum. Which has the longer wavelength?

A)the bullet
B)the proton
C)both the same

Question 52

In Heisenberg's formula, △p △x≥ h, the h symbolizes

A)Planck's constant.
B)an average value of Planck's constant.
C)the peak value of Planck's constant.
D)Planck's constant divided by 2π.
E)none of the above

Question 53

Quantum uncertainties are most predominant for simultaneously measuring the speed and location of

A)a baseball.
B)a spitball.
C)an electron.
D)none of the above

Question 54

In Heisenberg's formula, △p △x≥ h, the △ symbolizes

A)increase in.
B)decrease in.
C)change in.
D)uncertainty of.
E)certainty of.

Question 55

According to your textbook, popular confusion is lessened when applying Heisenberg's uncertainty principle by heeding the distinction between

A)momentum and energy.
B)energy and time.
C)passive observation and probing.

Question 56

In placing a cool thermometer into a hot cup of tea you likely are

A)affecting its temperature.
B)draining energy from the tea.
C)both of these
D)neither of these

Question 57

Heisenberg's uncertainty principle applies to

A)momentum and position.
B)energy and time.
C)both of these
D)neither of these

Question 58

When you adjust a telescope to get a clear image of Saturn's rings, in a small but measurable way you alter

A)the telescope.
B)Saturn's rings.
C)both of these
D)neither these

Question 59

In casually observing a cup of tea you are

A)affecting its temperature.
B)affecting its location.
C)both of these
D)neither of these

Question 60

Which of the following has the longer wavelength?

A)a low-energy electron
B)a high-energy electron
C)both the same
D)none of the above

Question 61

The more we know about a particle's position, the less we know about its

A)speed.
B)momentum.
C)kinetic energy.
D)all of the above
E)none of the above

Question 62

At the beach you see a friend facing away from you. Keeping quiet you can cause her to turn around by

A)staring intently at her back.
B)tossing small pebbles at her back.
C)although staring will be less effective, both will affect a turn-around.
D)none of the above

Question 63

The uncertainty principle tells us that the more information one has about the energy of an electron, the less certain one is about

A)its position.
B)the time it has that energy.
C)both of these
D)neither of these

Question 64

Casually sneaking a quick peek at a photo in your mobile phone

A)adds energy to the photo.
B)subtracts energy from the photo.
C)brings you into an observer-observed relationship that intrigues some science types.
D)changes the phone itself
E)none of the above

Question 65

A radiation detector measures radioactivity decay of a piece of radium by catching and counting alpha particles it emits. Making this measurement affects the

A)radiation rate of the piece of radium.
B)alpha particles that are caught and counted.
C)both of these
D)neither of these

Question 66

The idea of complementarity is evident in the

A)dual nature of light.
B)notion of opposites being components of a whole.
C)yin-yang symbol of Eastern cultures.
D)all of the above
E)none of the above

Question 67

According to quantum physics, measuring the temperature of lava from a distant volcano by photographing its color with a telescopic camera measurably affects the lava's temperature.

A)True
B)False
C)both of these depending on circumstances

Question 68

According to the principle of complementarity, wavelike and particle-like properties of light

A)only slightly contradict each other.
B)very much contradict each other.
C)make up a wholeness that better describes nature.
D)none of the above

Question 69

When Niels Bohr was knighted for his contributions to physics, he chose for his coat of arms

A)a model of the planetary atom.
B)a rendition of an energy-level diagram.
C)the yin-yang symbol of Eastern culture.
D)none of the above

Question 70

A key feature of the theory of chaos is

A)unpredictability.
B)very small initial differences can lead to very large eventual differences.
C)the randomness of molecular motion makes prediction difficult.
D)even orderly systems are seen to be disorderly when carefully studied.