Deck 42: Nuclear Energy: Efects and Uses of Radiation

Question 1

Thermal neutrons are

A)neutrons that are hot.
B)neutrons that are cold.
C)neutrons with a kinetic energy of about 1/40 eV
D)neutrons that are used for heating.
E)neutrons that are used for cooling.

Answer 1

neutrons with a kinetic energy of about 1/40 eV

Question 2

Which Uranium isotope is the most commonly occurring isotope?

A)U-235
B)U-236
C)U-237
D)U-238
E)U-239

Answer 2

U-238

Question 3

A fusion reaction generates energy by combining lighter nuclei into a heavier nucleus, plus additional particles.

Answer 3

True

Question 4

How does the total mass of the products of a nuclear fission reaction compare to the mass of the original elements?

A)greater
B)less
C)the same
D)varies according to the reaction

Question 5

If the Q-value is less than zero for a nuclear reaction, the reaction is

A)exoergic.
B)endoergic.
C)endothermic.
D)exdoergic.
E)not possible.

Question 6

In references to nuclear chain reactions, what is meant by the term CRITICAL MASS?

Question 7

The Sun is powered by the proton-proton cycle.

Question 8

Discuss why it is impossible for a particle to decay into a single particle of less mass.

Question 9

In a nuclear reaction, what value is conserved in addition to electric charge, energy, and momentum?

A)atomic number
B)neutron number
C)nucleon number
D)all of the given answers
E)none of the given answers

Question 10

A moderator is inserted into a fission reaction to absorb neutrons and prevent additional fissions.

Question 11

A chain reaction can occur

A)in any uranium core.
B)when critical mass is reached.
C)when critical mass is exceeded.
D)in the center of the Sun.
E)when the coolant is too hot.

Question 12

A series of fission reactions in which subsequent reactions are initiated by the neutrons produced in the previous reactions is called a

A)critical reaction.
B)chain reaction.
C)usion reaction.
D)neutron catastrophe.
E)chemical reaction.

Question 13

The process during which a heavy nucleus such as uranium splits into two intermediate-sized nuclei after being struck by a neutron is referred to as

A)nuclear fission.
B)nuclear fusion.

Question 14

A nuclear reaction is said to be exothermic if the total kinetic energy is

A)less after the reaction than before.
B)equal both before and after the reaction.
C)greater after the reaction than before.
D)zero after the reaction.

Question 15

A nuclear reaction is said to be endothermic if the total kinetic energy is

A)less after the reaction than before.
B)equal both before and after the reaction.
C)greater after the reaction than before.
D)zero after the reaction.

Question 16

Discuss the problems involved in achieving controlled fusion as a source of energy.

Question 17

The fuel for nuclear fission is

A)H.
B)He.
C)Li.
D)U.
E)any radioactive material.

Question 18

If the Q-value is greater than zero for a nuclear reaction, the reaction is

A)exoergic.
B)endoergic.
C)endothermic.
D)exdoergic.
E)not possible.

Question 19

Photons associated with the magnetic field used in magnetic resonance imaging have considerably less energy than the photons used in CT scans.

Question 20

What is the meaning of the term "critical mass"?

A)This refers to the mass of the "critical" elements in a reactor, i.e., the uranium or plutonium.
B)This refers to the minimum amount of fissionable material required to sustain a chain reaction.
C)This refers to the maximum amount of fissionable material required to sustain a chain reaction.
D)This is the amount of mass needed to make a power reactor economically feasible.
E)This is the material which is just on the verge of becoming radioactive.

Question 21

The energy radiated by a star, such as the Sun, results from

A)beta decay.
B)alpha decay.
C)fission reactions.
D)fusion reactions.
E)gravitational collapse.

Question 22

What is the source of the energy the Sun radiates to us?

A)chemical reactions
B)nuclear fission reactions
C)nuclear fusion reactions
D)magnetic explosions
E)cosmic rays

Question 23

What kind of reactor produces more fissionable fuel than it consumes?

A)AOLA
B)LOCA
C)moderated
D)heavy water
E)breeder

Question 24

Which of the following is not used as a moderator material for nuclear reactors?

A)sodium
B)heavy water
C)graphite
D)boron
E)These are all used as a moderator material for nuclear reactors.

Question 25

Controlled fusion has been difficult to achieve primarily due to

A)the high temperatures required to overcome Coulomb repulsion.
B)negligible proton cross section.
C)the difficulty of slowing the fusion neutrons.
D)the weak interaction.

Question 26

Determine the missing product X in the reaction: + → X + 2( )

Question 27

A fusion reaction works because the binding energy of the resulting nucleus

A)is greater than the binding energy of the original nuclei.
B)is equal to the binding energy of the original nuclei.
C)is less than the binding energy of the original nuclei.
D)is released in the process.
E)is absorbed in the process.

Question 28

What type of scan is used to find the areas of the body where glucose metabolism is most intense?

A)PET scans
B)CT scans
C)MRI
D)NMR
E)radioactive iodine tracers

Question 29

All of the following are units used to describe radiation dosage in humans except

A)curie.
B)rad.
C)rem.
D)RBE.
E)sievert.

Question 30

How does the mass of the products of a nuclear fusion reaction compare to the mass of the original elements?

A)greater
B)less
C)the same
D)varies according to the reaction

Question 31

When uranium fissions, the fission fragments are

A)each about half the mass of the uranium nucleus.
B)about 2/5 and 3/5 the mass of the uranium nucleus.
C)about 1/3 and 2/3 the mass of the uranium nucleus.
D)about 1/4 and 3/4 the mass of the uranium nucleus.
E)about 1/5 and 4/5 the mass of the uranium nucleus.

Question 32

The fuel for nuclear fusion in the center of the Sun is

A)H.
B)He.
C)O.
D)U.
E)any radioactive material.

Question 33

The process during which small nuclei combine to form larger ones is referred to as

A)nuclear fission.
B)nuclear fusion.

Question 34

Fission fragments tend to be radioactive because they have

A)more protons than neutrons.
B)more neutrons than protons.
C)too many more protons than neutrons.
D)too many more neutrons than protons.
E)the same number of neutrons as protons.

Question 35

A unit that measures the effective dose of radiation in a human is the

A)curie.
B)RBE.
C)rad.
D)rem.
E)sievert.

Question 36

The chief hazard of radiation damage to living cells is

A)due to ionization.
B)due to heating.
C)due to the creation of chemical impurities.
D)the creation of new isotopes within the body.

Question 37

Which of the following best describes the process in which energy is released in a conventional nuclear reactor?

A)The radiation given off by a naturally radioactive substance, uranium, is collected and used to make steam.
B)Uranium is reacted with oxygen in a combustion process that releases large amounts of radioactivity and heat.
C)Deuterium and tritium are joined together to form helium.
D)Uranium, when bombarded by neutrons, splits into fragments and releases two or three neutrons, and these neutrons in turn strike more uranium nuclei that split, thereby setting off a chain reaction that releases energy.
E)A uranium nucleus is energized to an excited state by neutron irradiation, and it then decays by emitting beta rays and gamma rays that heat water and create steam.

Question 38

In a nuclear power reactor of the type used to generate electricity, a neutron bombards a uranium nucleus, causing it to split into two large pieces (fission fragments) plus two or three neutrons. Energy is released in this process in the form of electromagnetic radiation and kinetic energy. Which of the following is an accurate statement concerning what happens in such a fission process?

A)The electrical energy generated comes from the kinetic energy of the incident neutrons.
B)The electrical energy generated comes from chemical energy stored in the electron bonds of the uranium atom.
C)Electrical energy is generated because the fission fragments are electrically charged, whereas the uranium was electrically neutral.
D)An intermediate step involves the fusion of protons to form helium nuclei, and energy is released in this process.
E)The total mass of the particles after fission is less than the total mass of the particles (uranium nucleus plus one neutron) before fission, and this decrease in mass Δm is converted into energy E, where E = Δmc².

Question 39

What is the principal difference between a hydrogen bomb and a uranium bomb?

A)A uranium bomb is an atomic bomb, and a hydrogen bomb is a nuclear bomb.
B)A uranium bomb utilizes a fission reaction whereas a hydrogen bomb utilizes a fusion reaction.
C)Both work on the same principle, but the hydrogen bomb has a higher yield.
D)A hydrogen bomb converts mass into energy, whereas a uranium bomb does not.
E)One results in radioactive fallout, and the other does not.

Question 40

PET is an abbreviation for

A)photon-electron tunneling.
B)positron emission tomography.
C)photon emission tunneling.
D)photon emission tomography.
E)pericranial electromagnetic technique.

Question 41

Consider the fission reaction: + → 2 fission products + 2 n's
(a) Estimate the energy released in the reaction.
(b) If 3 neutrons had been released instead of 2, what energy would have been released?

Question 42

What is the missing term in this fission reaction: + → + ? + 4

A)
B)
C)
D)
E)

Question 43

In the fission reaction ²³⁵U + ¹n $\rightarrow$ ¹⁴¹Ba + ⁹²Kr + neutrons, the number of neutrons produced is

A)0.
B)4.
C)1.
D)3.
E)2.

Question 44

The threshold energy to initiate a certain nuclear reaction is 3.16 MeV and the Q for the reaction is -2.37 MeV. The stationary target is how many times as massive as the incident particle?

Question 45

What is the Q-value of the following reaction? ¹⁴N + ⁴He = ¹p + ¹⁷O
(14.003074) (4.002603) (1.007825) (16.999131)

A)11.91 MeV
B)1.191 MeV
C)-1.191 MeV
D)1.279 × 10^-3 MeV
E)-1.279 × 10^-3 MeV

Question 46

What is the Q value for the following reaction? ⁷Li + ¹p = ⁴He + ⁴He
(7.016005) (1.007825) (4.002603) (4.002603)

A)13.35 MeV
B)13.57 MeV
C)15.37 MeV
D)17.35 MeV
E)17.53 MeV

Question 47

When a neutron collides with a uranium-235 nucleus it can induce a variety of fission reactions. One such reaction is + $\rightarrow$ + + 2 . Given the following mass values: , 139.921620 u; , 93.915367 u; , 235.043924 u; , 1.008665 u, how much energy is released in this reaction? 1 u = 931.494 MeV/c².

A)185 MeV
B)202 MeV
C)32.6 MeV
D)65.7 MeV
E)98.6 MeV

Question 48

If a reactor produces an average power of 1000 MW for a year, how much mass is turned into energy?

A)0.35 kg
B)1.75 kg
C)384 kg
D)1.1 × 10⁸ kg
E)3.3 × 10⁸ kg

Question 49

If a 2.0-MeV neutron released in a fission reaction loses half its energy in each moderator collision, how many collisions are needed to bring it to (1/25) eV?

A)6
B)18
C)26
D)30
E)4

Question 50

Determine the missing reaction product:
¹n + ²³⁵U = ¹⁴¹Ba + ________ + 3(¹n )

Question 51

Find the Q value of the following reaction: + → + (14.003074 u) (4.002603 u) (16.999131 u) (1.007825 u)

Question 52

Complete the following reaction:
¹n + ¹⁰B → ⁴He + ________

Question 53

A beam of protons is sent through a target and 60% get through. If the target then has its thickness doubled, what percent of the beam would then get through?

A)20%
B)36%
C)40%
D)60%
E)80%

Question 54

The Q value for a particular reaction is -2.4 MeV, and the reaction's threshold energy is 9.60 MeV. What is the ratio of the mass of the incident particle to the mass of the stationary target nucleus?

A)-0.75
B)0.25
C)3
D)4
E)5

Question 55

A beam of 10¹² neutrons/second is incident on an aluminum foil of thickness 10^-4 m. The cross section for absorption is 0.23 bn. What is the reaction rate for neutrons being absorbed?

A)1.4 × 10¹¹/s
B)1.4 × 10⁹/s
C)1.4 × 10⁸/s
D)1.4 × 10¹⁰/s
E)1.4 × 10¹²/s

Question 56

A proton strikes an Oxygen-18 nucleus producing Fluorine-18 and another particle. What other particle is produced by this nuclear reaction?

A)a neutron
B)an alpha particle
C)a gamma particle
D)a β^- particle
E)a β⁺ particle

Question 57

Complete the following nuclear reaction: + → ________ +

Question 58

The thermal neutron cross section of a proton is 0.33 bn. If this cross-section were to represent the circular cross-sectional area of the proton presented to the neutron beam, what would be the radius of the proton?

A)1.2 x 10^-15 m
B)1.6 x 10^-15 m
C)3.2 x 10^-15 m
D)4.1 x 10^-15 m
E)5.2 x 10^-15 m

Question 59

In the fissioning of uranium, the typical amount of energy released per nucleon is

A)0.025 eV.
B)100 MeV
C)0.9 MeV.
D)200 MeV.
E)10 MeV

Question 60

Find the Q value of the following reaction: + → + (14.003074 u) (4.002603) (16.999131 u) (1.007825 u)

A)-0.001279 u
B)-0.002179 u
C)-0.003479 u
D)-0.007219 u
E)-0.009721 u

Question 61

Two deuterium nuclei, , fuse to produce a helium nucleus, , and a neutron. A neutral deuterium atom has a mass of 2.014102 u; a neutral helium atom has a mass of 3.016030 u; a neutral hydrogen atom has a mass of 1.007825 u; a neutron has a mass of 1.008665 u; and a proton has a mass of 1.007277 u. How much energy is released in the process? 1 u = 931.494 MeV/c².

A)3.27 MeV
B)3.57 MeV
C)4.00 MeV
D)4.50 MeV
E)6.58 MeV

Question 62

How much energy is released in the reaction ²H + ²H → ⁴He? [m(²H) = 2.012102 u, m(⁴He) = 4.002603 u]

A)20 MeV
B)18 MeV
C)13 MeV
D)12 MeV
E)36 MeV

Question 63

The isotope 99m Tc (half-life of 6.0 hours) is used in bone scans. How long does it take a quantity of 99m Tc to reduce to 1% of its initial activity?

A)0.06 hours
B)3.3 hours
C)33 hours
D)40 hours
E)slightly more than one month

Question 64

The reaction ²H + ²H → ³H + ¹H releases 4.03 MeV of energy. If one kilogram of deuterium were made to go through this reaction, how much energy would be produced?

A)9.7 × 10⁷ J
B)9.7 × 10¹³ J
C)1.9 × 10⁷ J
D)1.9 × 10¹⁴ J
E)1.9 × 10¹¹ J

Question 65

When a neutron collides with a uranium-235 nucleus it can induce a variety of fission reactions. One such reaction is + $\rightarrow$ + + 2 . Given the following mass values: , 139.921620 u; , 93.915367 u; , 235.043924 u; , 1.008665 u what mass of uranium is needed to produce a 10-kiloton yield? 1 u = 1.660540 x 10^-27 kg;
1 kiloton = 5.0 x 10¹² J.

A)0.57 kg
B)0.66 kg
C)6.58 kg
D)3.85 kg
E)1.10 kg

Question 66

Two deuterium nuclei, , fuse to produce a tritium nucleus, , and a hydrogen nucleus. A neutral deuterium atom has a mass of 2.014102 u; a neutral tritium atom has a mass of 3.016050 u; a neutral hydrogen atom has a mass of 1.007825 u; a neutron has a mass of 1.008665 u; and a proton has a mass of 1.007277 u. How much energy is released in the process? 1 u = 931.494 MeV/c².

A)3.03 MeV
B)3.53 MeV
C)4.03 MeV
D)4.53 MeV
E)6.58 MeV

Question 67

An X-ray technician takes an average of ten X-rays per day and receives 2.5 mrad per X-ray. What is the total dose the technician receives in 250 working days?

A)2.50 rem
B)5.00 rem
C)6.25 rem
D)7.75 rem
E)12.5 rem

Question 68

If the internal temperature of the sun is 15 x 10⁶ K, what is the average kinetic energy of protons in this environment?

A)0.040 eV
B)1.3 keV
C)1.9 keV
D)1.3 MeV
E)1.9 MeV

Question 69

If a reactor produces an average power of 1000 MW for a year, how much ²³⁵U is used up assuming 200 MeV are released per fission?

A)0.35 kg
B)1.75 kg
C)384 kg
D)1.1 × 10⁸ kg
E)3.3 × 10⁸ kg