Deck 13: The Quantum Universe

Question 1

Can two microscopic [or quantum] particles be entangled even when they are exerting no forces on each other?

A) Yes, they could be entangled but so far apart as to exert no significant forces on each other.
B) Yes, because they can still communicate with each other by means of electromagnetic radiation.
C) No, because entanglement occurs only by means of the electromagnetic force and the other fundamental forces.
D) No, because in order for a particle to be trapped in the field of another particle, it must feel the second particle's force field.
E) No, because the psi field is actually a force field.

Answer 1

Yes, they could be entangled but so far apart as to exert no significant forces on each other.

Question 2

As a particle's uncertainty in position gets smaller, its uncertainty in velocity

A) must decrease enough to satisfy the uncertainty principle.
B) must remain unchanged.
C) must increase enough to satisfy the uncertainty principle.

Answer 2

must increase enough to satisfy the uncertainty principle.

Question 3

Which quantum characteristic(s) would quantum computers exploit in order to achieve great computational power with only a few individual quantum elements or "qubits"?

A) Entanglement.
B) Wave packets.
C) Magnetic resonance.
D) Uncertainty.
E) Both uncertainty and entanglement.

Answer 3

Both uncertainty and entanglement.

Question 4

Which one has the largest range of possibilities [or quantum uncertainty range]?

A) helium atom
B) proton
C) water molecule
D) electron
E) dust grain

Question 5

The spectrum of the hydrogen atom differs from the spectrum of the helium atom due to

A) their different energy levels.
B) the different frequencies of their emitted photons.
C) Both of the above.
D) Neither of the above.

Question 6

In the position- entanglement experiment, one of the two particles impacts at a particular point on one of the screens. Is the other particle affected by this observation, and if so, how?

A) Yes, the other particle transitions into a new quantum state a little later, after the force exerted by the first particle has had time to reach the second particle.
B) Yes, the other particle immediately makes a transition into a different quantum state, even though the two particles are some distance apart.
C) Yes, the other particle then ceases to feel the force exerted by the first particle.
D) No, the other particle is not affected because they are separate particles.
E) No, the other particle is not affected because observations [such as the impact of a particle] cannot in themselves alter other objects in the real physical world.

Question 7

Which of the following is an example of Heisenberg's uncertainty principle?

A) The unpredictability of radioactive decay.
B) The unpredictability of a coin toss.
C) Both of the above.
D) The unpredictability of the weather.
E) All of the above.

Question 8

Referring to the figure above, which quantum jump produces the highest frequency?

A) nonsense-- quantum jumps don't produce radiation
B) from state 2 to state 1
C) from state 4 to state 3
D) from state 4 to state 1
E) Impossible to tell without further information

Question 9

According to quantum theory, the electron in a particular quantum state of the hydrogen atom has

A) a definite position.
B) a definite velocity.
C) a definite energy.
D) All of the above.
E) None of the above.

Question 10

Suppose that a certain atom had just 4 different energy levels. How many different frequencies could be emitted by this atom?

A) 10
B) 4
C) 6
D) 16
E) an infinite number.

Question 11

The difference between the "ground state" and an "excited state" for a hydrogen atom is

A) the atom can radiate when it is in an excited state, but not when it is in a ground state.
B) the excited state has more energy.
C) Both of the above.
D) a ground state's matter field is a standing wave but an excited state's matter field is not a standing wave.
E) All of the above.

Question 12

What happens in the double- slit experiment with electrons if we place an electron detector just behind one of the slits?

A) This provides no information concerning which slit each electron comes through, and has no effect on the pattern formed on the screen.
B) This tells us which slit each electron comes through, and has no effect on the pattern formed on the screen.
C) We can then predict the precise point at which the electron will strike the screen.
D) This tells us which slit each electron comes through, but it also changes the pattern formed on the screen.
E) This provides no information concerning which slit each electron comes through, but it does change the pattern formed on the screen.

Question 13

When an atom undergoes a "quantum jump" into a lower- energy state, the atom

A) absorbs an electron.
B) emits an electron.
C) emits a photon.
D) absorbs a photon.
E) None of the above.

Question 14

A certain type of atom has only four energy levels, as shown in the figure above. The "spectral lines" produced by this element are all visible, except for one ultra- violet line. The quantum jump that produces the UV line is

A) state 4 to 3.
B) state 1 to 4
C) state 4 to 1.
D) state 2 to 1.
E) Impossible to determine without further information.

Question 15

One philosophical difference between Newtonian and modern physics is that, unlike modern physics, Newtonian physics

A) has no way of dealing with energy and other abstract concepts.
B) emphasizes the interaction between the observer and the thing observed.
C) makes predictions that contain an essential element of uncertainty.
D) is based on abstract concepts and is thus difficult or impossible to picture.
E) assumes that the universe is made of separate and independently existing parts.

Question 16

Which of the following is a consequence of Heisenberg's uncertainty principle?

A) The overall layout of the universe.
B) The uncertainties involved in determining a person's genetic inheritance when DNA molecules are combined.
C) Both of the above.
D) The unpredictability of radioactive decay.
E) All of the above.

Question 17

Which of the following does quantum theory agree with?

A) Microscopic particles, rather than the macroscopic world, form the fundamental reality.
B) It is possible to analyze physical phenomena and physical systems by separating them into their component parts and studying those parts individually.
C) Future events are entirely predetermined, or predictable.
D) All of the above.
E) None of the above.

Question 18

Referring to the figure above, the photons of lowest energy are produced by

A) the ground state.
B) quantum jumps from state 4 to 3.
C) quantum jumps from state to state 1.
D) state 4.
E) Impossible to determine without further information.

Question 19

According to Heisenberg's uncertainty principle, electrons are more unpredictable than protons. This is because electrons

A) have a smaller volume
B) have a smaller mass.
C) interact more strongly with other particles.
D) interact more weakly (i.e., less strongly) with other particles.
E) are negatively charged rather than positively charged.

Question 20

In quantum theory, what happens if an electron's wave packet is squeezed into a smaller region of space?

A) You increase the electron's uncertainty in position while decreasing its uncertainty in velocity.
B) You decrease the electrons uncertainty in velocity while leaving its uncertainty in position unaffected.
C) You decrease the electron's uncertainty in position while increasing its uncertainty in velocity.
D) You decrease the electrons uncertainty in position while leaving its uncertainty in velocity unaffected.
E) You decrease the electron's uncertainty in velocity and also decrease its uncertainty in position.

Question 21

In discussing the electron double- slit experiment, we studied a graph of the extended wave pattern formed on the screen by each electron's matter field. Did this graph show a single electron's matter field just before, or just after, the electron strikes the screen, and why?

A) This is the matter field just after impact, because each electron actually spreads out over a large region and strikes all over this region, in a wave pattern.
B) This is the matter field just before impact; after impact the matter field transforms into two distinct parts, with one part appearing on the screen directly behind each slit.
C) This is the matter field just before impact; after impact, the electron acquires a definite velocity.
D) This is the matter field just before impact; after impact the matter field collapses into a small region around the impact.
E) This is the matter field just after impact, because the electron can strike the screen at a wide variety of specific places, and these places form a field pattern.

Question 22

Although electrons do not normally have precise positions, you can cause an electron to have a (fairly) precise position by

A) measuring its momentum at an earlier time.
B) measuring its position.
C) measuring its wavelength.
D) measuring both its position and velocity at an earlier time.
E) measuring its velocity.

Question 23

A key component of one type of spectroscope for visible radiation is the

A) mirror for separating the radiation beam.
B) electrostatic plate for bending and separating the radiation beam.
C) magnet for bending the radiation beam.
D) prism for separating the radiation beam.
E) filter for separating the different gases.

Question 24

Which has the more predictable behavior, an electron or a proton, and why?

A) A proton, because it does feel the nuclear force.
B) An electron, because of its smaller charge.
C) A proton, because of its larger mass.
D) An electron, because of its smaller mass.
E) An electron, because it doesn't feel the nuclear force.

Question 25

According to the nonlocality principle,

A) each microscopic particle is always spread out over a large region of space.
B) forces such as gravity and the electromagnetic force can be felt even at a distance.
C) nature is inherently uncertain.
D) two particles can respond to each other instantaneously, no matter how far apart they are.
E) two particles can always be in contact with each other by electromagnetic waves that travel at light velocity.

Question 26

Which of the following is a feature of quantum physics that is not valid according to Newtonian physics?

A) Nature is non- local, i.e., separated objects are sometimes instantaneously connected with each other.
B) The universe is made of tiny particles.
C) The principle of conservation of energy.
D) The future is entirely determined by the present.
E) The second law of thermodynamics.

Question 27

According to Bell's nonlocality principle,

A) a particle always has an irreducible uncertainty in its position or in its velocity or both.
B) entangled particles exhibit correlations that are explainable only by real, instantaneous connections between them.
C) any two particles must always exert forces on each other no matter how far apart they are.
D) any small change at one point must eventually cause large changes at distant points.
E) the act of observation always disturbs the object being observed.

Question 28

Suppose that a certain atom has just the 4 different energy levels shown in the figure above. Which quantum jump produces radiation with the shortest wavelength?

A) nonsense-- quantum jumps don't produce radiation
B) from state 2 to state 1
C) from state 4 to state 3
D) from state 4 to state 1
E) Impossible to tell without further information

Question 29

The matter field of a hydrogen atom could best be described as

A) a collection of electrons.
B) an electromagnetic wave.
C) a cloud of photons.
D) a probability pattern.

Question 30

One problem with the planetary model of the atom is that it

A) cannot explain the observed spectrum of the various types of atoms.
B) cannot explain boiling, freezing, and other transitions between the three common states of matter.
C) cannot explain electrical effects.

Question 31

Referring to the figure above, the matter- wave representing the electrons will be spread out the furthest from the nucleus when

A) the atom is in state 1.
B) the atom makes a quantum jump from state 4 to state 1.
C) the atom is feeling angry and alienated from society.
D) the atom is in state 4.
E) the atom makes a quantum jump from state 4 to state 3.

Question 32

What happens to an electron's wave packet if an accurate velocity measurement is performed?

A) It suddenly changes to a new wave packet having a very small uncertainty in position, but a large uncertainty in velocity.
B) Neither the wave packet nor the electron is affected by the measurement.
C) It suddenly changes to a new wave packet having a very small uncertainty in velocity, but a large uncertainty in position.
D) The wave packet is unaffected by the measurement, even though the electron itself makes a sudden change of state that is caused by the measurement.
E) It suddenly changes to a new wave packet having small uncertainties in both velocity and position.

Question 33

If a microscopic particle's uncertainty in velocity is reduced,

A) its uncertainty in position must increase enough to satisfy the uncertainty principle.
B) its uncertainty in position must remain unchanged.
C) its uncertainty in position must decrease enough to satisfy the uncertainty principle.

Question 34

One way to describe the "allowed" matter fields for an isolated hydrogen atom is that they are

A) the possible standing waves that will just "fit" around the nucleus.
B) the patterns that are spherically symmetric relative to the nucleus.
C) the possible shapes of the electron's charge that will just "fit" around the nucleus.
D) the electromagnetic fields that can be produced by the orbiting electron.
E) the various possible elliptical shapes for the orbit of the electron.

Question 35

John Bell is known as

A) the first person to actually eat a pizza.
B) the discoverer of the uncertainty principle.
C) the discoverer of the nonlocality principle.
D) the originator of the most widely- accepted philosophical interpretation of quantum theory.
E) the originator of the "many worlds interpretation" of quantum theory.

Question 36

In the double- slit experiment with electrons, suppose that the observer uses a detector to determine through which slit the electron actually passes. Does this affect the outcome of the experiment, and why or why not?

A) No, the pattern on the screen remains an interference pattern, regardless of the detector.
B) No, the pattern on the screen remains a non- interference pattern, regardless of the detector.
C) Yes, the detector causes the pattern on the screen to suddenly change from an interference pattern [with no detector] to two tiny spots directly behind each slit [with the detector].
D) Yes, the detector causes the pattern on the screen to suddenly change from an interference pattern [with no detector] to a non- interference pattern [with the detector].
E) Yes, the detector causes the pattern on the screen to suddenly change from a non- interference pattern [with no detector] to an interference pattern [with the detector].

Question 37

If Planck's constant were smaller than it actually is, how would the uncertainty principle be affected?

A) Quantum uncertainties would then extend to lower- mass particles, such as electrons.
B) Quantum uncertainties would be unaffected, but quantum jumps would be smaller.
C) Quantum uncertainties would be larger.
D) Quantum uncertainties would be smaller.
E) Quantum uncertainties would be unaffected, but quantum jumps would occur in a shorter time.

Question 38

According to the uncertainty principle, a particle such as an electron

A) has a precise position and a precise velocity, but the observer is unable to determine them.
B) is entirely made of sausage.
C) does not have a precise position or a precise velocity.
D) must have uncertainties in position and velocity that remain smaller than a particular prescribed value.
E) can have arbitrarily small simultaneous uncertainties in both position and velocity, although neither uncertainty can be zero.

Question 39

The entanglement experiment described in the textbook demonstrates that

A) a particle's energy is not continuous but is instead quantized in specific, discrete "bundles."
B) any reduction of a particle's position uncertainty is accompanied by an increase in its velocity uncertainty, as predicted by quantum theory.
C) any attempt to observe which slit a particle goes through, in the electron double- slit experiment, causes the interference pattern to switch to a non- interference pattern.
D) quantum theory's prediction of instantaneous non- local connections between separated particles is incorrect.
E) two separated particles can exhibit instantaneous non- local connections, as predicted by quantum theory.

Question 40

Do quantum uncertainties differ in any essential way from the uncertainty in a coin flip, and why or why not?

A) You can make money with coin flips but you can't make a red cent out of quantum theory.
B) They don't differ in any essential way-- both uncertainties are "inherent in nature" and cannot be removed by additional information.
C) With sufficient information, a coin flip's outcome can be predicted, but no amount of information can remove quantum uncertainties.
D) With sufficient information, quantum uncertainties can be removed, but no amount of information can make a coin flip predictable.
E) They don't differ in any essential way-- both are a consequence of the observer's insufficient information and can be removed by obtaining additional information.

Question 41

A quantum computer built from 4 qubits

A) must be in only one of its 16 possible quantum states.
B) can be in all 16 of its 16 possible quantum states, simultaneously.
C) must be in only one of its 4 possible quantum states.
D) can be in all 8 of its 8 possible quantum states, simultaneously.
E) can be in all 4 of its 4 possible quantum states, simultaneously.

Question 42

In one experiment, a photon entered one detector and that detector then indicated the slit through which a second photon passed in a double- slit experiment that was some distance away from the first detector. This experiment shows that

A) macroscopic detectors always exert actual forces on microscopic particles, even at a distance.
B) it is possible for a detector to obtain complete information about a particle's simultaneous position and velocity, without causing a sudden change in the EM field.
C) microscopic events are subject to Heisenberg's uncertainty principle whenever detectors are involved.
D) macroscopic detectors can have non- local effects even on objects that they do not directly interact with.
E) whenever a detector exerts an actual force on a particle, it causes the particles EM field to suddenly change.

Question 43

Which of the following statements best describes Einstein's contributions and views about quantum theory?

A) Although his work on the photoelectric effect was an important contribution to quantum theory, Einstein never really accepted quantum theory.
B) He didn't make any significant contributions to the theory, but he did accept quantum theory.
C) Despite his important work on relativity, Einstein didn't make any important contributions to quantum theory, and furthermore he never really accepted quantum theory.
D) Although his work on the quantum theory of atoms was an important contribution, Einstein never really accepted quantum theory.
E) His work on the photoelectric effect was an important contribution to quantum theory, and he accepted the theory as a correct description of the microscopic world.

Question 44

Werner Heisenberg's main contribution to the development of quantum theory was

A) the uncertainty principle.
B) his explanation of the photoelectric effect, in terms of photons.
C) the nonlocality principle.
D) a method for predicting the position at which electrons or other particles will strike the viewing screen in such experiments as the electron double- slit experiment.
E) a method for predicting the overall statistical patterns that appear in the electron double- slit experiment and other experiments using microscopic particles.

Question 45

According to Heisenberg's uncertainty principle, which of the following particles is the most predictable, in other words which has the smallest overall uncertainties as to its position and velocity?

A) electron
B) hydrogen atom
C) proton
D) neutron
E) gold atom

Question 46

When we speak of the "spectrum" of a radiation source, we are referring to

A) the set of velocities that its particles actually have.
B) the overall range of velocities that its particles could possibly have.
C) the various types of atoms and molecules of which the source is composed.
D) the various frequencies at which its particles collide with each other.
E) the set of frequencies that the source can emit.

Question 47

Which of the following is a consequence of Heisenberg's uncertainty principle?

A) The fact that atoms don't collapse.
B) The uncertainties involved in determining a person's genetic inheritance when DNA molecules are combined.
C) The unpredictability of radioactive decay.
D) All of the above.
E) None of the above.

Question 48

In the electron double- slit experiment with electrons, what happens when a detector is used to determine through which slit the electron actually passes?

A) The pattern on the screen suddenly becomes a non- interference pattern.
B) The pattern on the screen suddenly becomes an wave- interference pattern.
C) Batman arrives.
D) The electron then acquires both a precise velocity and a precise position.
E) The electron suddenly jumps into a state of higher energy.

Question 49

A "standing wave" is a wave that

A) vibrates and moves from one place to another but whose shape does not change.
B) vibrates at zero amplitude.
C) a wave that is in the process of reversing its direction of motion.
D) doesn't vibrate.
E) vibrates but whose "loops" don't move from one place to another.

Question 50

When an atom emits radiation

A) a photon makes a quantum jump from one quantum state to another.
B) a proton strikes a neutron to create a photon.
C) it emits a small portion of its electric charge.
D) an electron makes a quantum jump from one quantum state to another.
E) an electron moves in precisely one complete orbit around the nucleus.

Question 51

According to quantum theory,

A) individual microscopic events are inherently unpredictable.
B) nature is "non- local," i.e., instantaneously connected across a distance.
C) Both of the above.
D) the overall statistics of large numbers of microscopic events are inherently unpredictable.
E) All of the above.

Question 52

What happens to a particle's wave packet when a highly accurate position measurement is performed?

A) It makes a gradual transition to a state of greater uncertainty in position but smaller uncertainty in velocity.
B) It suddenly makes a transition into a state of smaller uncertainty in position and greater uncertainty in velocity.
C) It suddenly makes a transition into a state of greater uncertainty in position but smaller uncertainty in velocity.
D) It suddenly makes a transition into a state of smaller uncertainty in position, with no change in its uncertainty in velocity.
E) It makes a gradual transition to a state of smaller uncertainty in position and greater uncertainty in velocity.

Question 53

When an atom emits a photon, the atom's mass

A) decreases slightly.
B) increases slightly.
C) remains exactly the same.
D) could do any of the above.
E) becomes negative-- i.e., less than zero.

Question 54

Which one has the smallest range of possibilities [or quantum uncertainty range]?

A) water molecule
B) dust grain
C) electron
D) proton
E) helium atom

Question 55

Which of the following experiments demonstrates the fact that the mere act of observation, or detection, causes changes in the microscopic world?

A) The electron double- slit experiment with a detector placed behind one of the slits.
B) The photoelectric effect that results from the detection of light.
C) The interference pattern that is detected on the screen in the electron double- slit experiment.
D) The detection of radioactive decay using a Geiger counter.
E) None of the above.

Question 56

Which of the following is a feature of Newtonian physics that is not correct according to quantum physics?

A) Tiny particles form the fundamental reality.
B) Future events are predictable.
C) Nature is "local," i.e., there are no instantaneous connections at a distance.
D) All of the above.

Question 57

The standard "picture" of the hydrogen atom as a tiny proton with an electron moving in an ellipse around it is extremely oversimplified. The main thing wrong with this picture is

A) the electron should be pictured as a spread- out matter field.
B) actually there are several electrons going around in the hydrogen atom
C) the electron is actually much larger than the proton.
D) the path is actually much more complicated than the elliptical path pictured.
E) Actually this picture is not oversimplified.

Question 58

In measurements made with spectroscopes, why is the light first sent through a narrow slit?

A) to increase the interference effects
B) to produce broad-- i.e., wide-- spectral lines on the screen
C) to increase the bending effect by the prism
D) to produce narrow spectral lines on the screen
E) to increase the amount of light hitting the prism.

Question 59

If we describe the double- slit experiment entirely in terms of electrons instead of in terms of fields, then which of the following is the best description of what one individual electron does in this experiment?

A) It doesn't go through the slits at all.
B) It goes through either one or the other slit, and the observer does know which one it actually goes through.
C) It goes through both slits.
D) It turns into the tooth fairy.
E) It goes through either one or the other slit, but the observer does not know which one it actually goes through.

Question 60

If two electrons are entangled, then

A) if one particle suddenly alters its wave packet, the other must also.
B) both are part of a single matter wave.
C) Both of the above.
D) they must exert forces on each other.
E) All of the above.

Question 61

Of all the various .TYPEs of scientific measurements that are possible to make, which type of scientific measurement has given us the most information about the physical universe?

A) Spatial measurements, i.e., measurements of distance, area, and volume.
B) Energetics, i.e., measurements of the total energy produced by various physical processes.
C) Thermometry i.e., measurements of temperature.
D) Spectroscopy, i.e., measurements of spectra.
E) Measurements of mass and weight.

Question 62

According to the philosophical ideas associated with quantum theory,

A) science describes the objective universe, uninfluenced by humans.
B) microscopic particles do not have precise positions or velocities.
C) microscopic particles form the fundamental reality.
D) All of the above.
E) None of the above.

Question 63

Does a baseball have large quantum uncertainties, or small ones?

A) Small, because the baseball has such a large mass.
B) Large, because the baseball has such a large mass.
C) Large, because the baseball has such a small mass.
D) Small, because the baseball has such a small mass.
E) It's impossible to tell unless we know how fast the baseball is moving.

Question 64

Suppose a certain type of atom had just 5 different energy levels. How many different frequencies could be emitted by a gas composed of atoms of this type?

A) 4
B) 10
C) 25
D) 5
E) an infinite number

Question 65

Which one of the following physicists strongly disagreed with quantum theory, arguing that some of the theory's predictions could not be correct?

A) Erwin Schroedinger
B) Max Born
C) John Bell
D) Niels Bohr
E) Albert Einstein

Question 66

If Planck's constant were smaller than it is, would this affect the sizes of atoms?

A) No, because atomic orbits do not exhibit quantum uncertainties.
B) No, because the sizes of atoms are determined by the electromagnetic force acting between the nucleus and the electrons and this force is not affected by quantum phenomena.
C) Yes, atoms would then be larger than they are because the electromagnetic force would be weaker.
D) Yes, atoms would then be larger than they are, because quantum uncertainties would be larger.
E) Yes, atoms would then be smaller than they are, because quantum uncertainties would be smaller.

Question 67

Radioactive decay furnishes a good example of

A) the wavelike nature of microscopic particle.
B) nuclear fusion.
C) quantum non- locality.
D) nuclear fission.
E) quantum uncertainties.

Question 68

The most accurate measurements known are

A) mass measurements.
B) spectroscopic measurements.
C) made with thermometers.
D) measurements of electric charge.

Question 69

A certain type of atom has only four energy levels, as shown in the figure above. The total number of spectral lines produced by this element is

A) 6.
B) 4.
C) 10.
D) 3.
E) impossible to determine without further information.

Question 70

Which of the following is a feature of quantum physics but not a feature of Newtonian physics?

A) Determinism: The future is entirely determined by the present.
B) The principle of conservation of energy.
C) Force at a distance: Objects can exert forces on other objects that are some distance away, across empty space.
D) The observation process must be included as part of the theory.
E) All of the above.

Question 71

One philosophical difference between Newtonian and quantum physics is

A) Newtonian physics is unable to deal with such abstractions as energy, whereas quantum physics is able to deal with these abstractions.
B) nature is predictable according to Newtonian physics, but nature is unpredictable according to quantum theory.
C) nature is unpredictable according to Newtonian physics, but nature is predictable according to quantum theory.
D) Newtonian physics is now known to be incorrect, but scientists have proven that quantum physics is absolutely correct.
E) Newtonian physics emphasizes the measurement process whereas quantum physics recognizes that the measurement process should not be included in physical theories.

Question 72

Although electrons do not normally have precise velocities, you can cause an electron to have a (fairly) precise velocity by

A) measuring both its position and velocity at an earlier time.
B) measuring its frequency.
C) measuring its velocity.
D) measuring its position.
E) measuring the force it exerts on another electron.

Question 73

In quantum theory, a "wave packet"

A) represents one particle having a specific position but a range of possible velocities.
B) represents one particle having a range of possible positions but a specific velocity.
C) represents many particles, each one having a range of possible positions and a range of possible velocities.
D) represents one particle having a range of possible positions and a range of possible velocities.
E) represents many particles, each one having both a specific position and a specific velocity.

Question 74

In quantum theory, "entanglement" refers to

A) the communication that occurs when one particle sends an electromagnetic wave to another.
B) the spreading out of a single particle's EM field or matter field over a region of space.
C) the forces that two particles can exert on each other even when they are separated.
D) two particles sharing a single quantum field (EM field or matter field) with each other.
E) the fact that a particle can get trapped in the electric field of another particle.