Deck 31: Light Quanta

Question 1

In the photoelectric effect,the greater the frequency of the illuminating light,the greater the

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

Answer 1

maximum velocity of ejected electrons.

Question 2

In the double-slit experiment with electrons,the electrons arrive at the screen in a

A)particle-like way with a pattern that is particle-like.
B)particle-like way with a pattern that is wave-like.
C)wave-like way with a pattern that is particle-like.
D)wave-like way with a pattern that is wave-like.

Answer 2

particle-like way with a pattern that is wave-like.

Question 3

In the relationship E = hf for a photon emitted from an atom,the symbol E is used to represent the energy

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

Answer 3

both of these

Question 4

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

A)photoelectric effect
B)double-slit experiment
C)neither

Question 5

A lump of energy associated with light is called a

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

Question 6

In the equation E = hf,the f stands for

A)wave frequency as defined for sound,radio,and light waves.
B)the smaller wavelengths of visible light.
C)frequency characteristic of quantum phenomena.
D)none of these

Question 7

According to quantum physics,looking at a star through a telescope

A)affects the processes occurring in the star.
B)has no effect on the processes occurring in the star.

Question 8

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

A)a baseball.
B)a spitball.
C)an electron.

Question 9

According to the 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 these

Question 10

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

A)pi.
B)Planck's constant.
C)the photon's speed.
D)the photon's wavelength.
E)not known.

Question 11

A quantum of light is called a(n)

A)proton.
B)neutron.
C)electron.
D)notron.
E)none of these

Question 12

Which has more energy per photon?

A)red light
B)blue light
C)Both have the same energy.

Question 13

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 these

Question 14

Light behaves primarily as a wave when it

A)travels from one place to another.
B)interacts with matter.

Question 15

Which of the following photons has the greatest energy?

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

Question 16

The photoelectric effect best demonstrates the

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

Question 17

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 18

Which has less energy per photon?

A)red light
B)blue light
C)Both have the same energy.

Question 19

The uncertainty principle applies not only to momentum and position,but also to energy and time.This statement is

Question 20

Light behaves primarily as a particle when it

A)travels from one place to another.
B)interacts with matter.

Question 21

Which of the following forms an interference pattern when directed toward two suitably spaced slits?

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

Question 22

Two beams of light,a red beam and a blue beam,have the same energy.The beam with the greater number of photons is the

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

Question 23

According to the uncertainty principle,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 these
E)none of these

Question 24

Two photons have the same wavelength.They also have the same

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

Question 25

If a proton and an electron have identical momenta,the longer wavelength belongs to the

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

Question 26

When a clean surface of potassium metal is exposed to blue light,electrons are emitted.If the intensity of the blue light is increased,which of the following will also increase?

A)the number of electrons ejected per second
B)the maximum kinetic energy of the ejected electrons
C)the threshold frequency of the ejected electrons
D)the time lag between the absorption of blue light and the start of emission of the electrons
E)none of these

Question 27

A photosensitive surface is illuminated with both blue and violet light.The light that will cause the most electrons to be ejected is the

A)blue light.
B)violet light.
C)Both eject the same number.
D)not enough information given

Question 28

To study the energy of photoelectrons we measure

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

Question 29

Which of the following has the longer wavelength?

A)a low-energy electron
B)a high-energy electron
C)Both have the same wavelength.

Question 30

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

A)the bullet
B)the proton
C)Both have the same wavelength.

Question 31

According to quantum physics,measuring the velocity of a tiny particle with an electromagnet

A)affects the velocity of the particle.
B)has no effect on the velocity of the particle.

Question 32

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 33

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

A)the electron
B)the baseball
C)Both have the same wavelength.

Question 34

A radiation detector measures the radioactivity of a piece of radium by catching and counting alpha particles it emits.According to quantum physics,making this measurement affects the

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

Question 35

Which of the following is not quantized?

A)energy
B)radiation
C)number of people in a room
D)electric charge
E)All are quantized.

Question 36

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

A)affects the temperature of the lava.
B)has no effect on the temperature of the lava.

Question 37

In the photoelectric effect,doubling the frequency of incident light will cause the maximum energy of ejected electrons to

A)double.
B)increase,but not double.
C)more than double.
D)decrease.

Question 38

In the photoelectric effect,electrons ejected from bound states in the 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 39

Which of the following are conserved when a photon collides with an electron?

A)momentum,energy,and velocity
B)momentum and energy
C)momentum and velocity
D)energy and velocity
E)None of the above choices are correct.

Question 40

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

A)the electron
B)the proton
C)Both have the same wavelength.

Question 41

The phenomenon that can be 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 choices are correct.

Question 42

According to the correspondence principle,a new theory is valid if it

A)overlaps and agrees where the old theory works.
B)accounts for confirmed results from the old theory.
C)predicts the same correct results as the old theory.
D)all of these
E)none of these