Deck 41: Nuclear Physics and Radioactivity

Question 1

The atomic mass unit is defined as

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

Answer 1

one twelfth the mass of a carbon-12 atom.

Question 2

The nuclei of different isotopes of a given element have the same number of

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

Answer 2

protons.

Question 3

Heavier stable nuclei tend to have

A)half as many protons as neutrons.
B)the same number of neutrons and protons.
C)more neutrons than protons.
D)no trend in relative number of neutrons and protons.
E)more protons than neutrons.

Answer 3

more neutrons than protons.

Question 4

The proton is slightly more massive than the neutron.

Question 5

Except for the lightest nuclei, the average binding energy per nucleon is about

A)12 MeV.
B)4 MeV.
C)6 MeV.
D)10 MeV.
E)8 MeV.

Question 6

Going from medium mass nuclei to a heavy nuclei, the average binding energy per nucleon

A)decreases.
B)behaves randomly.
C)remains constant.
D)increases.
E)doubles.

Question 7

If an atom's atomic number is given by Z, its atomic mass by A, and its neutron number by N, which of the following is correct?

A)N = A + Z
B)N = Z - A
C)N = A - Z
D)N = 2A + Z
E)N = A + 2Z

Question 8

All nuclei of a given element have the same number of neutrons.

Question 9

The mass of an atom is

A)approximately equally divided between protons and electrons.
B)approximately equally divided between neutrons, protons, and electrons.
C)evenly divided between the nucleus and the surrounding electron cloud.
D)concentrated in the cloud of electrons surrounding the nucleus.
E)concentrated in the nucleus.

Question 10

The symbols Z, A, and N respectively stand for

A)neutron number, atomic mass number, atomic number.
B)atomic number, atomic mass number, neutron number.
C)atomic number, neutron number, atomic mass number.
D)atomic mass number, atomic number, neutron number.
E)atomic mass number, proton number, nucleon number.

Question 11

Compared to the masses of its separate protons and neutrons, the total mass of a stable nucleus is always

A)less.
B)the same.
C)greater.
D)zero.
E)varies from atom to atom.

Question 12

When nucleons join to form a stable nucleus, energy is

A)destroyed.
B)absorbed.
C)released.
D)not transferred.
E)either absorbed or released depending on nucleons involved.

Question 13

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

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

Question 14

The strong nuclear force acts only on neutral particles.

Question 15

The difference in the masses of a neutron and proton is

A)one.
B)equal to the mass of an electron.
C)less than the mass of an electron.
D)more than the mass of an electron.
E)zero.

Question 16

Compared to the electrostatic force, the nuclear force between adjacent protons in a nucleus is

A)much weaker.
B)only slightly weaker.
C)about the same size.
D)only slightly larger.
E)much larger.

Question 17

A nucleon is

A)a neutron or a proton.
B)a nucleus made of neutrons only.
C)a neutron or proton when in the nucleus.
D)a neutron, proton, or positron when in the nucleus.
E)a neutron or positron when in the nucleus.

Question 18

Atoms with the same atomic number but with different numbers of neutrons are referred to as

A)positrons.
B)nucleons.
C)nuclides.
D)isotopes.
E)none of the given answers

Question 19

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

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

Question 20

The competition between the electrostatic force between the protons in a nucleus and the strong nuclear force determines whether a nucleus is stable.

Question 21

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

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

Question 22

There is a limit to the size of a stable nucleus because of

A)the limited range of the strong nuclear force.
B)the weakness of the electrostatic force.
C)the weakness of the gravitational force.
D)the weakness of the weak nuclear force.
E)none of the given answers

Question 23

In beta decay, it is found that the energy of the emitted electrons varies and is always less than what is calculated on the basis of the parent and daughter nuclei. This is evidence for the existence of another particle called the

A)gluon.
B)meson.
C)neutrino.
D)quark.
E)positrons.

Question 24

In beta minus decay, the number of protons in the nucleus

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

Question 25

In all three types of radioactive decay, what value is conserved in addition to electric charge, energy, and momentum?

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

Question 26

The nuclei of are also known as

A)α particles.
B)β particles.
C)γ rays.
D)X-rays.
E)K-rays.

Question 27

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 beta particle by the weak force.

Question 28

When a gamma ray is emitted from an unstable nucleus,

A)the number of neutrons and the number of protons drop by two.
B)the number of neutrons drops by one and the number of protons increases by one.
C)the number of protons drops by one and the number of neutrons increases by one.
D)there is no change in either the number of neutrons or the number of protons.
E)none of the given answers

Question 29

Gamma rays can penetrate

A)air only.
B)a piece of paper.
C)several millimeters of aluminum.
D)several centimeters of lead.
E)several meters of iron.

Question 30

In beta minus decay, the number of neutrons in the nucleus

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

Question 31

In alpha decay, the Q-value and the kinetic energy of the alpha particle

A)have no trend in the relative size.
B)are different with the Q-value larger.
C)are different with the kinetic energy larger.
D)are the same.
E)cannot be determined.

Question 32

Which of the following statements concerning the nuclear force is false?

A)The nuclear force is very short-ranged.
B)The nuclear force is very weak and much smaller in relative magnitude than the electrostatic and gravitational forces.
C)The nuclear force is attractive and not repulsive.
D)The nuclear force acts on both protons and neutrons.
E)The nuclear is one of only four known types of forces in nature.

Question 33

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

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

Question 34

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

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

Question 35

A β^- particle is also known as

A)an electron.
B)a protron.
C)a positron.
D)a helium nucleus.
E)a photon.

Question 36

Beta rays can penetrate

A)air only.
B)a piece of paper.
C)several millimeters of aluminum.
D)several centimeters of lead.
E)several meters of iron.

Question 37

Which of the following is most nearly the same as a gamma ray?

A)an alpha particle
B)a beta ray
C)visible light
D)a proton
E)a neutron

Question 38

A β⁺ particle is also known as

A)an electron.
B)a proton.
C)a positron.
D)a helium nucleus.
E)a photon.

Question 39

Alpha rays can penetrate

A)air only.
B)a piece of paper.
C)several millimeters of aluminum.
D)several centimeters of lead.
E)several meters of iron.

Question 40

Gamma rays are emitted

A)often after beta decay.
B)often after alpha decay.
C)often from metastable states.
D)in all of the above.
E)in none of the above.

Question 41

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

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

Question 42

The atomic number and mass number for calcium 39 are 20 and 39, respectively.
(a) How many nucleons are in one atom?
(b) How many electrons are in one atom?
(c) How many protons are in one atom?
(d) How many neutrons are in one atom?

Question 43

In a nucleus, the number of protons, neutrons, and electrons is

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

Question 44

The mass of ¹H is 1.007825 u and the mass of ¹n is 1.008665 u. The mass of ¹²C is 12.000000 u, of ¹³N is 13.005739 u, and of ¹⁴N is 14.003074 u. What is the binding energy of the last proton in ¹³N?

A)2.5 MeV
B)1.9 MeV
C)9.8 MeV
D)10.6 MeV
E)3.8 MeV

Question 45

An element has an atomic mass number of 14 and atomic number 6.
(a) How many protons does it have?
(b) How many neutrons does it have?

Question 46

What is the nuclear radius of ⁹⁰Sr?

A)4.0 × 10^-15 m
B)1.2 × 10^-15 m
C)1.1 × 10^-13 m
D)5.4 × 10^-15 m
E)3.3 × 10^-13 m

Question 47

The type of detector that uses liquid hydrogen is a

A)Geiger tube.
B)scintillation counter.
C)cloud chamber.
D)bubble chamber.
E)spark chamber.

Question 48

The mass of ¹H is 1.007825 u and the mass of ¹n is 1.008665 u. The mass of ¹²C is 12.000000 u, of ¹³N is 13.005739 u, and of ¹⁴N is 14.003074 u. What is the binding energy of the last neutron in ¹⁴N?

A)10.6 MeV
B)9.8 MeV
C)1.9 MeV
D)2.5 MeV
E)3.8 MeV

Question 49

An aluminum foil 0.10 mm thick has how many aluminum atoms per square cm? (The density of aluminum is 2.7 × 10³ kg/ m³ and the atomic mass of aluminum is 27.)

A)6 × 10¹⁷
B)6 × 10²⁰
C)6 × 10²⁴
D)6 × 10⁹
E)6 × 10³⁰

Question 50

The neutral deuterium atom, , has a mass of 2.014102 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 of the nucleus? 1 u = 931.494 MeV/c².

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

Question 51

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

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

Question 52

In radioactive dating, carbon-14 is often used. This nucleus emits a single beta particle when it decays. When this happens, the resulting nucleus is

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

Question 53

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

A)It remains constant.
B)It increases.
C)It decreases.
D)It could do any of these.

Question 54

Cloud chambers have been replaced by bubble chambers because

A)the radioactive clouds were too dangerous to work with.
B)the density of fluids is greater than the density of vapors.
C)bubble chambers tend to be larger and more expensive.
D)gamma rays are visible in bubble chambers, but not in cloud chambers.

Question 55

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

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

Question 56

If a nucleus had a diameter of 8.0 × 10^-15 m, what would its mass be in atomic mass units?

A)7
B)296
C)37
D)64
E)128

Question 57

The type of detector that uses a magnetic field to curve charged particles is a

A)Geiger tube.
B)scintillation counter.
C)cloud chamber.
D)bubble chamber.
E)spark chamber.

Question 58

What is the binding energy per nucleon for ? The neutral 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. 1 u = 931.494 MeV/c².

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

Question 59

The mass of ¹H is 1.007825 u and the mass of ¹n is 1.008665 u. The mass of ¹²C is 12.000000 u. What is the total binding energy of ¹²C?

A)7.7 MeV
B)92 MeV
C)0.099 MeV
D)46 MeV
E)15 MeV

Question 60

What is the density of the nucleus of ⁹⁰Sr?

A)greater than 3 × 10²⁰ kg/ m³ m³
B)90 kg/ m³
C)2.1 × 10¹⁹ kg/ m³
D)2.0 × 10¹⁵ kg/ m³
E)2.3 × 10¹⁷ kg/ m³

Question 61

An atom has 98 protons and 249 nucleons. If it undergoes alpha decay, what are the number of protons and nucleons, respectively, in the daughter nucleus?

A)100, 245
B)94, 247
C)96, 245
D)96, 247
E)100, 249

Question 62

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. Given the following mass values: , 4.002603 u; , 235.043924 u, what is the kinetic energy of the nucleus? 1 u =931.494 MeV/c².

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

Question 63

Francium-223 decays to radium-223 by emitting what kind of nuclear radiation?

A)Alpha
B)Beta minus
C)Beta plus
D)Gamma
E)X-rays.

Question 64

Americium-243 has a decay constant of 9.39 × 10^-5years^-1. How long will it take for a sample of americium to lose one-third of its nuclei?

A)2960 s
B)10.6 × 10³ years
C)4.32 × 10³ years
D)6.44 × 10³ years
E)7.84 × 10³ years

Question 65

Radium-226 decays into radon-222 plus an alpha particle. How much energy is released in this process? 1 u = 931.494 MeV/c². The relevant mass values are: , 4.002603 u; , 222.017570 u; , 226.025402 u.

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

Question 66

A radioactive sample has a half-life of 10 min. What fraction of the sample is left after 40 min?

A)1/2
B)1/4
C)1/8
D)1/16
E)1/32

Question 67

²⁴¹Am decays by alpha particle emission. The daughter isotope in this case is (the atomic numbers of Np, Pu, Am, Cm, and Bk are 91, 92, 93, 94, and 95 respectively)

A)(²³⁹Np.)
B)(²³⁷Np.)
C)(²⁴⁵Bk.)
D)(²³⁵Bk.)
E)not given.

Question 68

Rutherfordium-261 has a half-life of 1.08 min. What is the decay constant of rutherfordium?

A)0.0107 s^-1
B)0.0154 s^-1
C)1.87 s^-1
D)2.91 s^-1
E)0.344 s^-1

Question 69

Plutonium-239 decays into uranium-235 plus an alpha particle. The energy released in the process is 5.24 MeV. Given the following mass values: , 4.002603 u; , 235.043924 u; what is the mass value of ? 1 u = 931.494 MeV/c².

A)239.052157 u
B)239.027750 u
C)239.001889 u
D)238.9991889 u
E)238.988842 u

Question 70

A carbon-14 nucleus decays to a nitrogen-14 nucleus by beta 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?

A)0.00157 MeV
B)0.0157 MeV
C)0.157 MeV
D)1.57 MeV
E)15.7 MeV

Question 71

Uranium-238 decays into thorium-234 plus an alpha particle. How much energy is released in this process? 1 u = 931.494 MeV/c². The relevant mass values are: , 4.002603 u; , 234.043583 u; , 238.050786 u.

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

Question 72

An element with atomic number 6 undergoes β^- decay. Its atomic number is now

A)7.
B)6.
C)5.
D)3.
E)2.

Question 73

A certain substance has a half-life of 5.0 hours. How many nuclei of the substance are required to give an initial activity of 6.0 μCi? 1 Ci = 3.7 × 10¹⁰ Bq.

A)5.8 × 10⁹ nuclei
B)8.5 × 10⁸ nuclei
C)6.3 × 10⁸ nuclei
D)3.2 × 10⁹ nuclei
E)2.4 × 10⁹ nuclei

Question 74

The decay constant of radon is 0.181 day s^-1. A sample of radon contains 6.00 × 10⁸ radon atoms. How many atoms are left after 10.0 days?

A)9.82 × 10⁷
B)7.67 × 10⁷
C)8.34 × 10⁸
D)7.29 × 10⁸
E)8.56 × 10⁸

Question 75

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 76

An element with atomic number 88 goes through alpha decay. Its atomic number is now

A)80.
B)82.
C)84.
D)86.
E)88.

Question 77

Rutherfordium-261 has a half-life of 1.08 min. How long will it take for a sample of rutherfordium to lose one-third of its nuclei?

A)1.02 min
B)1.62 min
C)0.63 min
D)2.70 min
E)3.24 min

Question 78

Fermium-253 has a half-life of 3.00 days. A sample of fermium has 7.37 × 10⁷ nuclei. How long will it take for there to be only 3.36 × 10⁶ fermium nuclei in this sample?

A)2.75 days
B)9.80 days
C)13.4 days
D)15.7 days
E)58.6 days

Question 79

The number of radioactive nuclei in a particular sample decreases to one-eighth of its original number in 9 days. What is the half-life of these nuclei?

A)9/8 days
B)2 days
C)3 days
D)8 days
E)10 days

Question 80

The radioactivity due to carbon-14 measured in a piece of a wooden casket from an ancient burial site was found to produce 20 counts per minute from a given sample, whereas the same amount of carbon from a piece of living wood produced 160 counts per minute. The half-life of carbon-14, a beta emitter, is 5730 years. Thus we would estimate the age of the artifact to be about

A)5,700 years.
B)11,500 years.
C)14,800 years.
D)17,200 years.
E)23,000 years.