Deck 29: Nuclear Physics

Question 1

The atomic mass unit is defined as

A)the mass of a proton.
B)the mass of an electron.
C)the mass of a hydrogen-1 atom.
D)one twelfth the mass of a carbon-12 atom.
E)the mass of a carbon-12 nucleus.

Answer 1

D

Question 2

Write the standard nuclear notation for the following nuclei: hydrogen-2,sulfur-33,and lead-207.

Answer 2

H, S, Pb

Question 3

Atomic nuclei that are all isotopes of an element all have the same

A)number of nucleons.
B)mass.
C)number of protons.
D)number of neutrons.

Answer 3

C

Question 4

The atomic number of an atom is equal to the number of what particles in the nucleus?

A)protons
B)neutrons
C)nucleons
D)electrons
E)positrons.

Question 5

A fusion reaction releases energy 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 6

The symbol for a certain isotope of radium is Ra.How many nucleons are there in the nucleus of this isotope?

A)88
B)138
C)214
D)226
E)314

Question 7

The symbol for a certain isotope of strontium is Sr.What is the mass number of this isotope?

A)38
B)52
C)88
D)90
E)128

Question 8

The primary reason that very large nuclei are unstable is due to

A)the cumulative repulsive force of the protons.
B)the cumulative attractive force between the protons and the orbiting electrons.
C)the repulsive force between the neutrons and the protons.
D)the extreme weakness of the gravitational attraction of the protons.

Question 9

The atomic number and mass number for calcium-39 are 20 and 39,respectively.How many neutrons are in one atom?

A)1
B)19
C)20
D)39
E)59

Question 10

What is true of an element of atomic number 15 that has an isotope of mass number 32? (There could be more than one correct choice.)

A)the number of protons in the nucleus is 15.
B)the number of neutrons in the nucleus is 15.
C)the number of protons in the nucleus is 32.
D)the number of nucleons in the nucleus is 47.
E)the number of neutrons in the nucleus is 17.

Question 11

A β^- particle is also known as

A)an electron.
B)a positron.
C)a helium nucleus.
D)a high-energy photon.

Question 12

The mass number of an atom is equal to the number of what particles in the nucleus?

A)protons
B)neutrons
C)nucleons
D)electrons
E)positrons.

Question 13

The symbol for a certain isotope of polonium is Po.How many neutrons are there in the nucleus of this isotope?

A)84
B)130
C)214
D)298
E)314

Question 14

The binding energy per nucleon of a nucleus

A)increases steadily as we go to heavier elements.
B)decreases steadily as we go to heavier elements.
C)is approximately constant throughout the periodic table, except for very light nuclei.
D)has a maximum near iron in the periodic table and decreases after that for heavier elements.
E)has a minimum near iron in the periodic table and increases after that for heavier elements.

Question 15

In massive stars,three helium nuclei fuse together,forming a carbon nucleus,and this reaction heats the core of the star.The net mass of the three helium nuclei must therefore be

A)higher than that of the carbon nucleus.
B)less than that of the carbon nucleus.
C)the same as that of the carbon nucleus because mass is always conserved.
D)the same as that of the carbon nucleus because energy is always conserved.

Question 16

Name the first three isotopes of hydrogen,write their symbols in standard notation,and indicate which one is the most common and which one is the most unstable.

Question 17

An α particle is also known as

A)an electron.
B)a positron.
C)a helium nucleus.
D)a high-energy photon.

Question 18

All nuclei of a given element have the same number of

A)neutrons.
B)protons.
C)nucleons.
D)protons + neutrons.

Question 19

In a Nb nucleus,how many protons,neutrons,and electrons are found there?

A)41, 52, 93.
B)41, 52, 41.
C)52, 41, 41.
D)41, 52, 0.
E)93, 41, 93.

Question 20

An yttrium isotope has 39 protons and 50 neutrons in its nucleus.Which one of the following symbols accurately represents this isotope?

A) Y
B) Y
C) Y
D) Y
E) Y

Question 21

What are the mass number,the atomic number,and neutron number for each of the following particles?
(a)proton
(b)neutron
(c)alpha particle

Question 22

During β⁺ decay

A)a neutron is transformed to a proton.
B)a proton is transformed to a neutron.
C)a neutron is ejected from the nucleus.
D)a proton is ejected from the nucleus.
E)the number of nucleons decreases.

Question 23

When a β^- particle is emitted from an unstable nucleus,the atomic mass number of the nucleus

A)increases by 1.
B)decreases by 1.
C)increases by 2.
D)decreases by 2.
E)does not change.

Question 24

Polonium-216 decays to lead-212 by emitting what kind of nuclear radiation?

A)alpha
B)beta-minus
C)beta-plus
D)gamma
E)x-rays.

Question 25

A β⁺ particle is also known as

A)an electron.
B)a positron.
C)a helium nucleus.
D)a high-energy photon.

Question 26

The atom Fr decays to Ra by emitting what kind of nuclear radiation?

A)alpha
B)beta-minus
C)beta-plus
D)gamma
E)x-rays.

Question 27

The nuclei of He are also known as

A)α particles.
B)β particles.
C)γ rays.
D)x-rays.
E)positrons.

Question 28

A radioactive isotope of atomic number Z emits an alpha particle,and the daughter nucleus then emits a beta-minus particle.What is the atomic number of the resulting nucleus?

A)Z -1
B)Z + 1
C)Z - 2
D)Z - 3

Question 29

When a β^- particle is emitted from an unstable nucleus,the atomic number of the nucleus

A)increases by 1.
B)decreases by 1.
C)increases by 2.
D)decreases by 2.
E)does not change.

Question 30

In positron decay,the number of protons in the nucleus is

A)decreased by 1.
B)decreased by 2.
C)increased by 1.
D)increased by 2.
E)remains unchanged.

Question 31

A gamma ray is also known as

A)an electron.
B)a positron.
C)a helium nucleus.
D)a high-energy photon.

Question 32

In β^- decay,the number of neutrons in the nucleus is

A)decreased by 1.
B)decreased by 2.
C)increased by 1.
D)increased by 2.
E)remains unchanged.

Question 33

During β^- decay

A)a neutron is transformed to a proton.
B)a proton is transformed to a neutron.
C)a neutron is ejected from the nucleus.
D)a proton is ejected from the nucleus.
E)the number of nucleons increases.

Question 34

In β^- decay,the number of protons in the nucleus is

A)decreased by 1.
B)decreased by 2.
C)increased by 1.
D)increased by 2.
E)remains unchanged.

Question 35

In beta-minus decay

A)a proton is emitted.
B)a neutron is emitted.
C)an electron is emitted.
D)an electron decays into another particle.
E)a proton is transformed into a neutron.

Question 36

When a β⁺ particle is emitted from an unstable nucleus,the atomic number of the nucleus

A)increases by 1.
B)decreases by 1.
C)increases by 2.
D)decreases by 2.
E)does not change.

Question 37

What are the mass number A and the charge (in units of e)for each of the following particles or rays?
(a)beta-plus
(b)beta-minus
(c)gamma ray

Question 38

A radioactive isotope of atomic number Z emits a beta-minus particle,and then the daughter nucleus emits a gamma ray.What is the atomic number of the resulting nucleus after both processes?

A)Z - 1
B)Z + 1
C)Z - 2
D)Z - 3

Question 39

A β^- decay occurs in an unstable nucleus when

A)a proton is converted to an electron by the strong force.
B)a proton is converted to a neutron by the strong force.
C)a neutron is converted to a proton by the weak force.
D)a neutron is converted to an alpha particle by the weak force.
E)a neutron is converted to a positron by the weak force.

Question 40

What is the mass number of alpha particles?

A)1
B)2
C)3
D)4
E)6

Question 41

When an unstable nucleus decays by emitting an alpha particle,the atomic number Z of the nucleus

A)increases by 4.
B)increases by 2.
C)decreases by 2.
D)decreases by 4.
E)remains unchanged.

Question 42

The diameter of an atom is 1.4 × 10^-10 m and the diameter of its nucleus is 1.0 × 10^-14 m.What fraction of the atom's volume is occupied by its nucleus?

A)3.6 × 10^-13
B)7.1 × 10^-5
C)5.1 × 10^-9
D)2.6 × 10^-17

Question 43

In a head-on collision,an alpha particle (Z = 2)of energy bounces straight back from a nucleus of charge How close were the centers of the objects at closest approach? (1 eV = 1.60 × 10^-19 J,e = 1.60 × 10^-19 C,1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

A)2.81 × 10^-14 m
B)3.39 × 10^-12 m
C)6.56 × 10^-15 m
D)2.17 × 10^-14 m

Question 44

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

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

Question 45

Suppose the half-life of an isotope is 2 days.You purchase 10 grams of the isotope,but it was produced in a laboratory 4 days before it was delivered to you.How much of this isotope will you have 3 days after it was delivered to you?

A)more than 2.5 grams but less than 5 grams
B)2.5 grams
C)more than 1.25 grams but less than 2.5 grams
D)1.25 grams
E)less than 1.25 grams

Question 46

The main fuel for producing energy in the center of the sun is

A)helium.
B)hydrogen.
C)uranium.
D)any radioactive material.
E)oxygen.

Question 47

What happens to the half-life of a radioactive substance as it decays?

A)It remains constant.
B)It increases.
C)It decreases at a constant rate.
D)It decreases at an exponential rate.

Question 48

Modern in-air nuclear bomb tests have created an extra high level of ¹⁴C in our atmosphere.If future archaeologists date samples from this era,without knowing of this testing,will their carbon-14 dates be too young,too old,or correct? If correct,why?

A)Too young.
B)Too old.
C)Correct, since ¹⁴C from bomb tests is different from that produced naturally.
D)Correct, because modern biological materials do not gather ¹⁴C from bomb tests.

Question 49

In the first nuclear reaction observed,physicists saw an alpha particle (Z = 2)interact with a nitrogen nucleus in air (Z = 7)to produce a proton.The energy of the alpha particle was enough to enable the nuclei to touch in spite of the Coulomb repulsion.What distance (in fm)between the centers of the alpha particle and the nitrogen was reached? This determines a limit on the radius of the nitrogen nucleus.(1 eV = 1.60 × 10^-19 J,e = 1.60 × 10^-19 C,1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

A)0.37 fm
B)0.18 fm
C)0.05 fm
D)158.40 fm

Question 50

How many protons,neutrons,and nucleons are there in a carbon-14 nucleus?

Question 51

The chief hazard of radiation damage to living cells is

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

Question 52

Two radioactive isotopes,X and Y,both decay to stable products.The half-life of X is about a day,while that of Y is about a week.Suppose a radioactive sample consists of a mixture of these two nuclides.If the mixture is such that the activities arising from X and Y are initially equal,then a few days later the activity of the sample will be due

A)predominantly to Y.
B)predominantly to X.
C)entirely to Y.
D)to X and Y equally.

Question 53

The half-life of cobalt-60 is 5.3 years,while that of strontium-90 is about 29 years.Suppose you have samples of both isotopes,and that they initially contain equal numbers of atoms of these isotopes.How will the activities (number of decays per second)of the samples compare?

A)The activity of the cobalt-60 sample will be greater.
B)The activities cannot be compared without more information.
C)The activities will be equal.
D)The activity of the strontium-90 sample will be greater.

Question 54

Isotope A has a decay constant of 0.723 s^-1 and isotope B has a decay constant of 0.514 s^-1.Which isotope has a longer half-life?

A)isotope A
B)isotope B

Question 55

The half-life of cobalt-60 is 5.3 years,while that of strontium-90 is about 29 years.Suppose you have samples of both isotopes,and that they initially have the same activity (number of decays per second).What must be true of the numbers of cobalt-60 and strontium-90 nuclei in these samples?

A)There are more strontium-90 than cobalt-60 nuclei.
B)There are equal numbers of cobalt-60 and strontium-90 nuclei.
C)There are more cobalt-60 than strontium-90 nuclei.
D)It is not possible to compare numbers of nuclei without knowing the masses of the samples.

Question 56

If the half-life of a material is 45 years,how much of it will be left after 100 years?

A)more than 1/2
B)less than 1/2 but more than 1/4
C)more than 1/4 but less than 1/2
D)less than 1/4 but more than 1/8
E)less than 1/8

Question 57

Carbon-14 decays by β^- emission.What nucleus is left after this decay?

A)carbon-13
B)carbon-14
C)carbon-15
D)nitrogen-14
E)nitrogen-15

Question 58

When an unstable nucleus decays by emitting an alpha particle,the atomic mass number A of the nucleus

A)increases by 4.
B)increases by 2.
C)decreases by 2.
D)decreases by 4.
E)remains unchanged.

Question 59

A person receives an absorbed dose of protons of 20 millirads.The RBE of protons is 5.What is this person's equivalent dose in rem?

A)4 millirem
B)15 millirem
C)20 millirem
D)25 millirem
E)100 millirem

Question 60

What happens to the half-life of a radioactive substance as we increase its temperature?

A)It does not change.
B)It increases.
C)It decreases at a constant rate.
D)It decreases at an exponential rate.

Question 61

Uranium-238 decays into thorium-234 plus an alpha particle.The known masses are He: 4.002603 u Th: 234.043583 u U: 238.050786 u How much energy is released in this process? (1 u = 931.5 MeV/c²)

A)4.28 MeV
B)3.76 MeV
C)3.18 MeV
D)2.89 MeV
E)5.05 MeV

Question 62

How much energy is released when 0.60 μg of ³H have decayed to ³He? The mass of ³He is 3.0160293 u,the mass of ³H is 3.0160492 u,1 u = 931.5 MeV/c²,1 eV = 1.60 × 10^-19 J,and N_A = 6.022 × 10²³ molecules/mol.

Question 63

A carbon-14 nucleus decays to a nitrogen-14 nucleus by beta-minus decay.How much energy (in MeV)is released if carbon-14 has a mass of 14.003242 u and nitrogen-14 has a mass of 14.003074 u? (1 u = 931.5 MeV/c²)

A)0.0156 MeV
B)0.156 MeV
C)1.56 MeV
D)15.6 MeV

Question 64

When a stationary plutonium-239 nucleus decays into a uranium-235 nucleus plus an alpha particle,the energy released in the process is 5.24 MeV.The following masses are known: He: 4.002603 u U: 235.043924 u What is the kinetic energy of the U nucleus? (1 u = 931.5 MeV/c²)

A)0.0829 MeV
B)0.0837 MeV
C)0.0852 MeV
D)0.0863 MeV
E)0.0877 MeV

Question 65

Starting with U,assume that the following three decays occur in sequence:
(1)alpha decay
(2)beta-minus decay
(3)alpha decay
Determine the correct isotope that is left after each decay.

Question 66

A beryllium-8 nucleus at rest undergoes double alpha decay as follows: Be → He + He The known atomic masses are: He: 4.002603 u Be: 8.005305 u
What is the kinetic energy of each departing alpha particle? (1 u = 931.5 MeV/c²)

A)46 keV
B)65 keV
C)92 keV
D)130 keV
E)180 keV

Question 67

The neutral deuterium atom, H,has a mass of 2.014102 u; a neutral ordinary 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.What is the binding energy of the deuterium nucleus? (1 u = 931.5 MeV/c²)

A)1.1 MeV
B)1.7 MeV
C)2.2 MeV
D)2.9 MeV
E)3.4 MeV

Question 68

The neutral helium atom, He,has a mass of 4.002603 u,a neutron has a mass of 1.008665 u,a proton has a mass of 1.007277 u,and a neutral hydrogen atom has a mass of 1.007825 u.What is the binding energy of the He nucleus? (1 u = 931.5 MeV/c²)

A)20.5 MeV
B)22.4 MeV
C)27.3 MeV
D)28.3 MeV
E)23.4 MeV

Question 69

When a stationary plutonium-239, Pu,decays into uranium-235 plus an alpha particle,the energy released in the process is 5.24 MeV.The following masses are known: He: 4.002603 u U: 235.043924 u What is the mass of the Pu nucleus,in amu? (1 u = 931.494 MeV/c²)

A)239.05215 u
B)239.02775 u
C)239.00189 u
D)238.99919 u
E)238.98884 u

Question 70

The stability of Cl with respect to alpha,beta-plus and beta-minus decay is to be determined.The following atomic masses are known: He: 4.002603 u P: 31.973907 u S: 35.967081 u Cl: 35.968307 u Ar: 35.967546 u The Cl nucleus is

A)not subject to alpha, beta-plus or beta-minus decay.
B)subject to alpha decay only.
C)subject to beta-plus decay only.
D)subject to beta-minus decay only.
E)subject to beta-plus or beta-minus decay, but not to alpha decay.

Question 71

The radius R of a nucleus of mass number A is given by R = R₀ A^1/3,where R₀ = 1.2 × 10^-15 m,calculate the density of a nucleus that has contains 57 protons and 82 neutrons.The mass of a nucleon (proton or neutron)is 1.67 × 10^-27 kg.

Question 72

One of the fusion reactions that occurs in the sun is: He + He → He + H + H The following atomic masses are known: H: 1.007825 u He: 3.016029 u He: 4.002603 u
What is the reaction energy released in this fusion reaction? (1 u = 931.5 MeV/c²)

A)11 MeV
B)13 MeV
C)15 MeV
D)17 MeV
E)19 MeV

Question 73

Radium-226 decays into radon-222 plus an alpha particle.The relevant masses are He: 4.002603 u Rn: 222.017570 u Ra: 226.025402 u How much energy is released in this process? (1 u = 931.5 MeV/c²)

A)4.24 MeV
B)3.76 MeV
C)4.87 MeV
D)5.05 MeV
E)5.39 MeV

Question 74

Bismuth Bi is known to be radioactive.The stability of Bi with respect to alpha,beta-plus and beta-minus decay is to be determined.The following atomic masses are known: He: 4.002603 u Tl: 207.981998 u Pb: 211.991871 u Bi: 211.991255 u Po: 211.988842 u The Bi nucleus is

A)subject to alpha decay only.
B)subject to beta-plus decay only.
C)subject to beta-minus decay only.
D)subject to alpha or beta-plus decay, but not beta-minus decay.
E)subject to alpha or beta-minus decay, but not beta-plus decay.

Question 75

The stability of C with respect to alpha,beta-plus and beta-minus decay is to be determined.The following atomic masses are known: He: 4.002603 u Be: 7.016928 u B: 11.009305 u C: 11.011433 u N: 11.026742 u The C nucleus is

A)not subject to alpha, beta-plus or beta-minus decay.
B)subject to alpha decay only.
C)subject to beta-plus decay only.
D)subject to beta-minus decay only.
E)subject to beta-plus or beta-minus decay, but not to alpha decay.

Question 76

A summary of the nuclear reactions that power our sun is 4p → ⁴He + 2e^-,with masses of 938.272 MeV/c² for a proton,3727.38 MeV/c² for the helium nucleus,and 0.511 MeV/c² for each electron.How much energy is released by each of these reactions?

A)24.69 MeV
B)28.3 MeV
C)2790.13 MeV
D)279.01 MeV

Question 77

The carbon in our bodies was formed in nuclear reactions in long-dead stars.How much energy was released when the right number of ⁴He nuclei combined to make ^{12C? The mass of 4He is 3728.40 MeV/c2 and the mass of 12C is 11,177.93 MeV/c2.}

A)7.27 MeV
B)372 MeV
C)8.42 MeV
D)2.11 MeV

Question 78

Suppose that starting with ,the following sequence of decays occurs: first an alpha decay,then a beta-minus decay,and finally another alpha decay.What isotope is left after each one of the decays?

Question 79

The neutral Al atom has a mass of 26.981539 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.What is the binding energy per nucleon for Al? (1 u = 931.5 MeV/c²)

A)8.3 MeV
B)6.7 MeV
C)5.4 MeV
D)3.4 MeV
E)2.8 MeV

Question 80

The following masses are known: n 1.008665 u H 1.007825 u Ra 226.025403 u What is the binding energy of Ra? (1 u = 931.5 MeV/c²)

A)1700 MeV
B)1900 MeV
C)2100 MeV
D)2300 MeV
E)2500 MeV