Deck 29: The Nucleus

Question 1

The normal U.S. average annual radiation dose per person is about how many REM?

Answer 1

0.20

Question 2

Discuss what observations convinced Rutherford that the nucleus was very small and dense.

Answer 2

Alpha scattering from heavy nuclei produced much more backscattering than would be expected from a diffuse nuclear cloud. Only a dense compact nucleus of positive charge could account for the scattering at large angles.

Question 3

Why do the high-proton-number elements tend to get more unstable?

Answer 3

The repulsive electrostatic force between protons increases progressively as atomic number increases, but the nuclear attractive force is short range and the average distance between particles increases as the nucleus size increases.

Question 4

Name five different types of radiation detectors.

Question 5

J. J. Thomson

A) observed back-scattering from nuclei.
B) proposed the tiny central nucleus idea.
C) proposed the plum-pudding model.
D) discovered radium and polonium.
E) invented the particle detector tube.

Question 6

Ernest Rutherford

A) observed back-scattering from nuclei.
B) proposed the tiny central nucleus idea.
C) proposed the plum-pudding model.
D) invented the particle detector tube.
E) discovered radium and polonium.

Question 7

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

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

Question 8

The number of protons in a neutral atom is

A) equal to the number of neutrons.
B) equal to the number of electrons.
C) called the mass number.
D) the same for all elements.
E) zero.

Question 9

An atom's mass number is determined by the number of

A) protons in its nucleus.
B) nucleons in its nucleus.
C) electron masses in its nucleus.
D) neutrons in its nucleus.
E) alpha particles in its nucleus.

Question 10

Isotopes of an element have nuclei with

A) a different number of protons, and the same numbers of neutrons.
B) the same number of protons, but different numbers of electrons.
C) a different number of protons, and a different number of neutrons.
D) the same number of protons, but different numbers of neutrons.
E) the same number of protons, and the same number of neutrons.

Question 11

All isotopes are unstable which have proton number greater than

A) 83.
B) 12.
C) 73.
D) 78.
E) 26.

Question 12

When an alpha particle is emitted from an unstable nucleus, the atomic mass number of the nucleus

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

Question 13

When a neutron is emitted from an unstable nucleus, the atomic mass number of the nucleus

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

Question 14

When a $\beta$ + particle is emitted from an unstable nucleus, the atomic number of the nucleus

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

Question 15

Marie & Pierre Curie

A) discovered radioactivity.
B) proposed the plum-pudding model.
C) observed back-scattering from nuclei.
D) discovered radium and polonium.
E) proposed the tiny central nucleus idea.

Question 16

Henri Becquerel

A) proposed the tiny central nucleus idea.
B) discovered radioactivity.
C) invented the particle detector tube.
D) discovered radium and polonium.
E) observed back-scattering from nuclei.

Question 17

Which isotopes are radioactive?

A) none
B) some
C) odd numbered
D) even numbered
E) all

Question 18

When an alpha particle is emitted from an unstable nucleus, the atomic number of the nucleus

A) increases by 2.
B) decreases by 4.
C) decreases by 2.
D) increases by 4.
E) increases by 6.

Question 19

When a nucleus undergoes beta-minus decay, it changes into

A) a higher atomic number.
B) a higher neutron number.
C) a higher mass number.
D) another isotope of itself.
E) a lower proton number.

Question 20

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

Question 21

Cosmic rays react with what atmospheric atoms to produce carbon-14?

A) oxygen
B) carbon-12
C) helium
D) nitrogen
E) hydrogen

Question 22

Alpha decay reduces the atomic and mass numbers respectively by how much?

A) 2, 4
B) 4, 2
C) 4, 4
D) 2, 2

Question 23

A becquerel (Bq) is

A) 3.70 × 10¹⁰ decays/s in radium.
B) the SI unit of radioactivity (= 1 decay/s).
C) a dosage of 2.58 × 10^-4 C/kg.
D) 10^-2 J/kg.
E) the SI unit of absorbed dose = 1 J/kg = 100 rad.

Question 24

Carbon-14 dating can reliably date ancient archeological samples up to approximately how many years?

A) 5 thousand
B) 100 million
C) 10 billion
D) 50 thousand
E) 5 million

Question 25

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

A) It decreases.
B) It remains constant.
C) It increases.

Question 26

The binding energy of most nuclei is proportional to

A)
B) A².
C) A³.
D) Z².
E) A.

Question 27

Which of the following is NOT a nuclear "magic number"?

A) 8
B) 82
C) 28
D) 58
E) 20

Question 28

The binding energy per nucleon

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

Question 29

The neutron-proton stability curve of the isotopes of all elements will be plotted on a graph whose axes are shown in Figure 29-1.

The plot will look like

A) graph A.
B) graph B.
C) graph C.
D) graph D.

Question 30

Stable nuclei with mass numbers greater than 40 have

A) N > Z.
B) Z > N.
C) N > M.
D) M < N + Z.
E) M > N + Z.

Question 31

Which of the following combinations of nucleons would be the most likely to result in a stable nucleus? ("Odd" and "even" refer to the numbers of protons and neutrons in the nucleus.)

A) even protons, even neutrons
B) odd protons, odd neutrons
C) even protons, odd neutrons
D) odd protons, even neutrons

Question 32

A roentgen (R) is

A) a dosage of 2.58 × 10^-4 C/kg.
B) 3.70 × 10¹⁰ decays/s in radium.
C) the SI unit of absorbed dose = 1 J/kg = 100 rad.
D) the SI unit of radioactivity ( = 1 decay/s).
E) 10^-2 J/kg.

Question 33

A rad is

A) a dosage of 2.58 × 10^-4 C/kg.
B) the SI unit of radioactivity ( = 1 decay/s).
C) 3.70 × 10¹⁰ decays/s in radium.
D) 10^-2 J/kg.
E) the SI unit of absorbed dose = 1 J/kg = 100 rad.

Question 34

A gray (Gy) is

A) the SI unit of radioactivity (= 1 decay/s).
B) 10^-2 J/kg.
C) a dosage of 2.58 × 10^-4 C/kg.
D) the SI unit of absorbed dose = 1 J/kg = 100 rad.
E) 3.70 × 10¹⁰ decays/s in radium.

Question 35

An RBE

A) when multiplied into dosage, yields the effective dose.
B) is an SI unit of absorbed dose = 1 J/kg = 100 rad.
C) is equivalent to 3.70 × 10¹⁰ decays/s in radium.
D) is an effective dose of 1 Gy.
E) is 10^-2 J/kg.

Question 36

A sievert (Sv) is

A) the SI unit of absorbed dose = 1 J/kg = 100 rad.
B) 10^-2 J/kg.
C) the effective dose of 1 Gy.
D) 3.70 × 10¹⁰ decays/s in radium.
E) a dosage of 2.58 × 10^-4 C/kg.

Question 37

In which of the following application of technology in the home is radioactivity utilized?

A) a door-bell
B) a food sterilizer
C) a smoke detector
D) a humidifier

Question 38

A rem is

A) a dose that 3.70 × 10¹⁰ decays/s in radium.
B) produces same tissue damage as 1 rad.
C) the SI unit of absorbed dose = 1 J/kg = 100 rad.
D) a dosage of 2.58 × 10^-4 C/kg.
E) an effective dose (= (rads)(RBE)).

Question 39

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

A) Rad.
B) RBE.
C) rem.
D) Curie.
E) Sievert

Question 40

Which of the following have the least RBE (relative biological effectiveness)?

A) beta particles
B) slow neutrons
C) alpha particles
D) gamma rays
E) fast protons

Question 41

Donald Glazer

A) observed back-scattering from nuclei.
B) invented the particle detector tube.
C) invented the bubble chamber.
D) discovered radium and polonium.
E) discovered radioactivity.

Question 42

The type of detector that uses liquid hydrogen is a

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

Question 43

Hans Geiger

A) discovered radium and polonium.
B) invented the bubble chamber.
C) discovered radioactivity.
D) observed back-scattering from nuclei.
E) invented the particle detector tube.

Question 44

The type of detector that requires a magnetic field to "view" charged particles is a

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

Question 45

What are the mass number and the atomic number for each of the following:
(a) beta+?
(b) beta-?

Question 46

Complete the following nuclear decay equation:

Question 47

Complete the following nuclear decay equation:

Question 48

Complete the following nuclear decay equation:

Question 49

A nucleus ^M _A N undergoes 1 alpha decay and 3 beta minus decay s.
(a) What is the resulting nucleus?
(b) If there had been beta plus decays, instead of beta minus decays, what would be the resulting nucleus?

Question 50

Name the first three isotopes of hydrogen and their nuclide symbols, and indicate which is most common and which is most unstable.

Question 51

From a knowledge of the size and mass of a nucleus, one can estimate the density of nuclear material. Such a calculation shows that the density of nuclear matter is on the order of magnitude of

A) 10⁴ kg/m³.
B) 10¹¹ kg/m³.
C) 10² kg/m³.
D) 10¹⁷ kg/m³.
E) 10⁸ kg/m³.

Question 52

How many protons are there in the carbon-14 nucleus?

A) 1
B) 14
C) 6
D) 8
E) none

Question 53

If an element of atomic number 15 has an isotope of mass number 32

A) the number of protons in the nucleus is 17.
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 15.
E) the number of neutrons in the nucleus is 17.

Question 54

Heavy-water molecules have a mass number of

A) 20.
B) 10.
C) 3.
D) 12.
E) 18.

Question 55

Which has the greater half-life?

A) Strontum-90
B) Cobalt-60
C) Uranium-238
D) Oxygen-19
E) Hydrogen-3

Question 56

A radioactive substance with a half-life of 3 days has an initial activity of 0.24 Ci. What is its activity after 6 days?

A) 0.12 Ci
B) 0.02 Ci
C) 0.06 Ci
D) 0.23 Ci
E) 0.48 Ci

Question 57

Plutonium has a half life of 2.4 × 10⁴ years. How long does it take for 99% of the plutonium to decay?

A) 1.6 × 10² y
B) 1.6 × 10⁴ y
C) 1.6 × 10³ y
D) 1.6 × 10⁶ y
E) 1.6 × 10⁵ y

Question 58

The radioactivity due to Carbon-14 measured in a piece of a wooden casket from an ancient burial site was found to produce 20.0 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) 14,800 years
B) 17,200 years
C) 11,500 years
D) 20,000 years
E) 5,700 years

Question 59

Which isotope is used to define the ATOMIC MASS UNIT?

A) ¹H
B) ²H
C) ⁴He
D) ¹⁶O
E) ¹²C

Question 60

Which of the following elements would be expected to be most stable?

A) Platinum-195
B) Helium-3
C) Iron-56
D) Bismuth-209
E) Carbon-12

Question 61

Which is unstable?

A)
B)

C)

D)

E)

Question 62

The binding energy of a ¹⁷⁰Yb atom would be expected to be close to

A) 170. MeV.
B) 1.4 GeV.
C) 8. MeV.
D) 170. GeV.
E) 17. MeV.

Question 63

What is the binding energy of the ⁴He nucleus?

A) 10.77 MeV
B) 7.80 MeV
C) 14.15 MeV
D) 28.3 MeV
E) 20.36 MeV