Deck 17: Quantum Fields: Relativity Meets the Quantum

Question 1

The antiparticle of the electron is the

A) neutrino.
B) photon.
C) positron.
D) proton.
E) neutron.

Answer 1

positron.

Question 2

The first "generation" of strongly interacting particles consists of

A) the up quark and the electron.
B) the up quark and the down quark.
C) the electron and the electron neutrino.
D) the proton and the neutron.
E) the up quark and the gluon.

Answer 2

the up quark and the down quark.

Question 3

Two electrons, "A" and "B," traverse the same region of a bubble chamber. Which of the following would cause electron B's path to curve more strongly than electron A's path?

A) Electron B has a bad cold.
B) Electron B has a larger mass.
C) Electron B is moving slower.
D) Electron B is moving faster.
E) Electron B has a larger charge.

Answer 3

Electron B is moving slower.

Question 4

In the process of pair- creation by a high- energy photon, energy is

A) conserved.
B) created.
C) destroyed.

Question 5

In the process of pair- creation by a high- energy photon, matter is

A) created.
B) conserved.
C) destroyed.

Question 6

According to current theory, the proton is made of smaller particles known as

A) neutrinos.
B) quarks.
C) neutrons.
D) electrons.
E) mesons.

Question 7

According to the standard model of fundamental particles, some of the fundamental particles form the "bricks" of the universe, while others form the "cement." Which among the following is one of the fundamental "cement" particles?

A) positron
B) the proton
C) the Z particle
D) the neutrino
E) the quark

Question 8

Neutrinos are hard to detect because

A) they experience only the gravitational force.
B) they move so fast.
C) they experience only the weak force.
D) they have such a small mass.
E) All of the above.

Question 9

The reason neutrinos are so penetrating is that

A) they are very light.
B) they are very heavy.
C) they feel only the weak nuclear force, and gravity.
D) they move so fast.
E) they feel only strong nuclear force, and gravity.

Question 10

The gravitational force is to gravitons as the electromagnetic force is to

A) photons.
B) quarks.
C) neutrinos.
D) protons.
E) gluons.

Question 11

Which force is the most difficult to incorporate into a single unified theory of the fundamental forces?

A) the electromagnetic force
B) the weak force
C) the armed forces
D) centrifugal forces
E) the gravitational force

Question 12

One currently- used practical application of antimatter is in

A) the discovery of small cracks in metallic machinery such as airplane wings.
B) a popular breakfast cereal made of antimatter.
C) propulsion of space vehicles.
D) nuclear magnetic resonance (NMR) medical diagnosis.
E) positron emission tomography (PET) scans of the brain.

Question 13

Which of these can feel the electric force?

A) Z particle
B) neutrino
C) photon
D) All of the above.
E) None of the above.

Question 14

The positron was first predicted by

A) Heisenberg.
B) Einstein.
C) Elvis Presley.
D) Planck.
E) Dirac.

Question 15

Which of the following particles is most similar to a muon?

A) electron
B) neutrino
C) proton
D) quark
E) photon

Question 16

According to the current theory or "standard model" of elementary particles, which one of the following is truly an "elementary" particle?

A) neutron
B) proton
C) neutrino
D) All of the above.
E) None of the above.

Question 17

Which of the following are quanta of the electromagnetic field?

A) electrons
B) photons
C) Both of the above.
D) quarks
E) All of the above.

Question 18

The Higgs field, if it is discovered, is expected to interact with particles in such a way as to give those particles

A) the ability to exert forces.
B) good looks.
C) electric charge.
D) rest mass.
E) physical existence.

Question 19

Which of the following is an example of antimatter?

A) muon
B) neutron
C) neutrino
D) positron
E) electron

Question 20

According to quantum field theory, electrons

A) always come in pairs.
B) are the quanta of a matter field.
C) interact by exchanging quarks.
D) are the quanta of the electromagnetic field.
E) None of the above.

Question 21

Physicists are currently working to achieve a unification of

A) all of the fundamental forces.
B) matter and radiation.
C) apples and oranges.
D) Newtonian and quantum physics.
E) electricity and magnetism.

Question 22

The strong force is to gluons as the gravitational force is to

A) photons.
B) Z particles.
C) neutrinos.
D) quarks.
E) gravitons.

Question 23

According to the current theory or "standard model" of elementary particles, which one of the following is truly an "elementary" particle?

A) electron
B) quark
C) neutrino
D) All of the above.
E) None of the above.

Question 24

Which of the following demonstrates the indeterminacy inherent in the microscopic [or atomic- level] world?

A) radioactive decay
B) double slit experiment with electrons
C) Both of the above.
D) spontaneous creation of a positron- electron pair from a photon
E) All of the above.

Question 25

Which of the following are quanta of a matter field?

A) quarks
B) electrons
C) Both of the above.
D) photons
E) All of the above.

Question 26

We never find isolated, individual quarks because

A) whenever quarks are separated, the energy created by the separation creates new quark pairs.
B) the force between quarks is infinitely strong so they cannot be budged.
C) quarks immediately undergo radioactive decay when they are separated.
D) quarks are bound tightly together by neutrinos.
E) quarks are always attached to electrons.

Question 27

Which one or ones of the following forces extend over macroscopic distances?

A) the electromagnetic force
B) the gravitational force
C) Both of the above.
D) the strong force
E) all three: electromagnetic, gravitational, and strong

Question 28

Physicists use bubble chambers primarily for the purpose of

A) detecting fission.
B) taking bubble- baths.
C) detecting sub- atomic particles.
D) detecting radioactivity.
E) None of the above.

Question 29

In what way is electric charge related to photons?

A) Photons are electrically- charged particles.
B) Photons interact by exchanging electrically- charged particles.
C) Electrically- charged particles are made of photons.
D) Electrically- charged particles interact by exchanging photons.
E) They are not related at all.

Question 30

The W⁺ and W^- are "exchange particles" for

A) the gravitational force.
B) the strong force.
C) the electromagnetic force.
D) the frictional force.
E) the electroweak force.

Question 31

Quantum field theory arises out of the combination of

A) quantum theory and nuclear physics.
B) quantum theory and the big bang theory of the creation of the universe.
C) the general theory of relativity and quantum theory.
D) the special theory of relativity and quantum theory.
E) the special theory of relativity and the theory of electromagnetism.

Question 32

According to the current theory or "standard model" of elementary particles, which one of the following is truly an "elementary" particle?

A) electron
B) proton
C) neutron
D) All of the above.
E) None of the above.

Question 33

Neutrinos can feel

A) the strong force.
B) the electromagnetic force.
C) Both of the above.
D) the weak force.
E) None of the above.

Question 34

Scientists have recently discovered that

A) it is possible for neutrinos to spontaneously transmute from one of the three neutrino types to another.
B) some, or possibly all, types of neutrinos have rest mass.
C) Both of the above.
D) None of the above.

Question 35

How many "generations" of strongly interacting particles are there?

A) six
B) four
C) three
D) two
E) an infinite number

Question 36

The exchange particles for the strong force are

A) quarks.
B) photons.
C) W⁺, W^- , and Z.
D) neutrinos.
E) gluons.

Question 37

The basic idea of the "string" hypothesis is that the fundamental particles are

A) made of chocolate fudge.
B) very tiny hollow spheres.
C) tiny loops of infinitely slender material.
D) infinitely long and infinitely slender objects.
E) just geometric points (infinitely tiny points).

Question 38

According to quantum field theory, the essential reality is

A) a few fields.
B) electromagnetic radiation.
C) particles moving in empty space.
D) quarks, electrons, neutrinos, and their anti- particles.
E) chocolate fudge.

Question 39

In pair creation,

A) matter and energy are both created.
B) matter and energy are both conserved.
C) matter is conserved but energy is created.
D) matter is created but energy is conserved.
E) two oppositely- flavored pizzas are created.

Question 40

According to quantum field theory, the universe if made of

A) photons.
B) baseball fields.
C) particles moving in empty space.
D) electromagnetic fields.
E) quantized fields.

Question 41

Which of the following is an "exchange particle" for the electroweak force?

A) the photon
B) the Z particle
C) Both of the above.
D) the W⁺ and W^-
E) All of the above.

Question 42

According to recent theorizing in high energy physics,

A) it is impossible to create or destroy quarks.
B) we should be able to find isolated quarks.
C) protons and neutrons can be put together to form quarks.
D) All of the above.
E) None of the above.

Question 43

Why can we never create energy?

A) because matter is always conserved
B) because energy is always conserved
C) because it is impossible to create the fundamental particles such as electrons and protons
D) because of the equivalence of mass and energy
E) Actually, we do create energy frequently in the lab.

Question 44

The Higgs field, if it is discovered, is expected to interact

A) with every type of particle.
B) only with particles that have no rest mass.
C) only with particles that are not electrically charged.
D) only with particles that have rest mass.
E) only with particles that are electrically charged.

Question 45

The Planck length is the length at which

A) quarks are expected to be squeezed out of existence.
B) quantum gravitational effects are expected to become important.
C) electric charge becomes a meaningless concept.
D) strong nuclear force effects between quarks are expected to become important.
E) photons acquire mass and move slower than lightspeed.

Question 46

Let "m" represent the mass of an electron, and "c" represent the speed of light. In order to create an electron- positron pair, we must start with a photon whose energy is

A) at least mc².
B) at least 2mc².
C) at least 4mc².
D) any value greater than zero.
E) Actually it is impossible to create such pairs from photons.

Question 47

The positron is

A) the anti- particle to the electron.
B) one of the three particles that go together to make a proton.
C) identical to the neutron but with a positive charge.
D) only hypothetical at the present time.
E) the anti- particle to the proton.

Question 48

At the very small- scale level, matter is

A) very cold.
B) nearly at rest.
C) subject only to the strong nuclear force.
D) really made of tiny pieces of pizza.
E) in rapid motion.

Question 49

An atom of "anti- hydrogen" would be made of

A) a high- frequency photon and a low- frequency photon.
B) an anti- proton and a muon.
C) a proton and a positron.
D) a positron and an electron.
E) an anti- proton and a positron.

Question 50

Do neutrinos have mass, and how do we know?

A) No, because they are observed to move at lightspeed.
B) No, because we have observed that their paths remain straight as they pass through a magnetic field.
C) Yes, because we have observed them to move slower than lightspeed.
D) Yes, for both of the reasons listed in answers c and d.
E) Yes, because we have observed them to transmute from one of the three neutrino types to another.

Question 51

Is so- called "empty" space really empty?

A) Yes, because conservation of energy forbids the spontaneous creation of matter or radiation.
B) Yes, because nothing exists other than particles and empty space.
C) No, because all space is filled with a physical substance known as "ether."
D) No, because of random quantum fluctuations.
E) No, because neutrinos are always present at every point in the universe.

Question 52

Neutrinos

A) are extremely penetrating.
B) move at nearly lightspeed.
C) have zero or near- zero rest- mass.
D) have all of the above properties.
E) have none of the above properties.

Question 53

The least massive particle of matter is now thought to be

A) the neutron.
B) the neutrino.
C) the proton.
D) the photon.
E) the electron.

Question 54

How many "generations" of electroweak particles are there?

A) six
B) three
C) four
D) two
E) an infinite number

Question 55

Which of the following travel at or very near lightspeed?

A) neutrino
B) photon
C) Both of the above.
D) Z particle
E) All of the above.

Question 56

Why can we never create matter?

A) because matter is always conserved
B) because we aren't capable of creating another universal "big bang"
C) because it is impossible to create the fundamental particles such as electrons and protons
D) because energy is always conserved
E) Actually, we do create matter frequently in the lab.

Question 57

The first "generation" of electroweak particles consists of

A) the electron and the electron neutrino.
B) the proton and the neutron.
C) the electron, muon, and tauon.
D) the up quark and the down quark.
E) the electron neutrino, muon neutrino, and tau neutrino.

Question 58

The Higgs field, if it is discovered, will explain the origin of

A) rest mass.
B) the big bang.
C) gravity.
D) electric charge.
E) photons.

Question 59

According to quantum field theory, what happens when two charged particles exert forces on each other?

A) Electrons are exchanged between them.
B) The two particles exchange their matter fields with each other.
C) Each particle causes the other particle's matter field to vibrate more rapidly.
D) An electromagnetic wave passes from one particle to the other.
E) Photons are exchanged between them.

Question 60

One similarity between photons and Z particles is that

A) both are exchange particles for the electroweak force.
B) both have charge.
C) both travel at lightspeed.
D) both have mass.
E) both are exchange particles for the strong force.

Question 61

During a positron emission tomography (PET) scan of the brain,

A) radioactive fluorine creates positrons within the brain that are detected as they leave the patient.
B) an external positron beam is sent through the patient's brain and detected as it leaves the patient.
C) matter and antimatter annihilate within the brain to create positrons that are detected as they leave the patient.
D) positrons and electrons annihilate within the brain to create gamma photons that are detected as they leave the patient.
E) highly sensitive detectors measure the positrons that are naturally emitted by the human body.

Question 62

The Planck time is

A) the time it takes for light to travel across-- or around-- the entire universe.
B) the time when the cosmic background radiation originated.
C) the time it takes for an electron in an unexcited hydrogen atom to orbit the nucleus one time.
D) the time required for pair creation.
E) the shortest time that has any physical meaning.

Question 63

How was the positron discovered?

A) By creating them in very high energy collisions of heavy nuclei such as gold nuclei.
B) By observing the cloud chamber tracks of high energy gamma rays as they created positron- electron pairs.
C) By observing the cloud chamber tracks of cosmic rays as they passed through a metal plate.
D) By allowing protons to collide in a particle accelerator.
E) By allowing electrons to collide in a particle accelerator.

Question 64

In pair creation, an electron- positron pair is created from

A) nothing.
B) a photon.
C) a neutron.
D) a neutrino.
E) a rabbit.

Question 65

According to the standard model of fundamental particles, some of the fundamental particles form the "bricks" of the universe, while others form the "cement." Which among the following is one of the fundamental bricks?

A) the photon
B) the Z particle
C) the gluon
D) the proton
E) the quark

Question 66

Which of the following particles is most similar to an electron?

A) photon
B) neutrino
C) proton
D) quark
E) muon

Question 67

An anti- proton would have

A) no charge and positive mass.
B) negative charge and positive mass.
C) negative charge and negative mass.
D) positive charge and positive mass.
E) positive charge and negative mass.

Question 68

Which of the following are quanta?

A) electrons
B) photons
C) Both of the above.
D) neutrinos
E) All of the above.