Deck 13: The Atomic Nucleus and Radioactivity

Question 1

Which of the following statements about radiation is true?

A)Your body contains a number of radioactive isotopes.
B)One rem is enough to kill approximately 50 percent of the average population.
C)Radiation damages cells beyond repair.
D)Several small exposures over time has the same negative effect as one large exposure that totals the same amount.
E)Radiation can make you glow in the dark.

Answer 1

A

Question 2

Which of the following professions would likely have the highest occupational exposure to radiation per year?

A)airline pilot
B)quarterback for the Denver Broncos
C)center for the L.A. Lakers
D)deep sea diver
E)lifeguard

Answer 2

A

Question 3

Which of the beams is due to a positively charged helium nucleus?

A)a
B)b
C)c
D)all of the above
E)none of the above

Answer 3

C

Question 4

What is a rem?

A)A rem is a unit for measuring radiation exposure.
B)A rem is the maximum exposure limit for occupational safety.
C)Rem stands for Rapid Electron Motion.
D)A rem is the number of radiation particles absorbed per second.
E)Rem is an '80s rock group.

Question 5

You are given three radioactive samples (α, β, and γ)and can only dispose of one. The other two you must keep, one in your hand, the other in your pocket. How would you minimize your exposure risk?

A)keep α in hand, keep β in pocket, and dispose of γ
B)dispose of α, keep β in hand, and keep γ in pocket
C)dispose of α, keep β in pocket and keep γ in hand
D)keep α in pocket, dispose of β, and keep γ in hand
E)keep α in hand, dispose of β, and keep γ in pocket

Question 6

Which of the beams is due to a high energy electron?

A)a
B)b
C)c
D)all of the above
E)none of the above

Question 7

Which of the beams is actually composed of particles?

A)a
B)b
C)c
D)a and c
E)all of the above

Question 8

Which of the following provides the minimum amount of protection you need to block the following form of radiation? alpha

A)lead suit
B)suntan lotion
C)thick leather
D)T-shirt
E)none of the above

Question 9

Which of the following sources of radiation provides most of our yearly exposure?

A)background radiation
B)smoke detectors
C)living near nuclear power plants
D)televisions (cathode ray tubes)
E)dental and medical X-rays

Question 10

Which of the following provides the minimum amount of protection you need to block the following form of radiation? gamma

A)lead suit
B)suntan lotion
C)thick leather
D)T-shirt
E)none of the above

Question 11

Radioactivity is a tendency for an element or a material to ________.

A)emit radiation
B)emit light
C)emit electrons
D)glow in the dark
E)radiate heat

Question 12

Which of the following statements about radiation is true?

A)Radiation can be a useful tool. Like fire, it is only dangerous when misused.
B)Radiation is new: It is a man-made phenomenon.
C)Radiation has no beneficial health applications.
D)all of the above
E)only A or B

Question 13

Which of the beams is due to an energetic light wave?

A)a
B)b
C)c
D)all of the above
E)none of the above

Question 14

Which of the beams is due to alpha particles?

A)a
B)b
C)c
D)all of the above
E)none of the above

Question 15

People who work around radioactivity wear film badges to monitor the amount of radiation that reaches their bodies. These badges consist of small pieces of photographic film enclosed in a light-proof wrapper. What kind of radiation do these devices monitor?

A)Alpha radiation
B)Beta radiation
C)Gamma radiation
D)all of the above

Question 16

Is it at all possible for a hydrogen nucleus to emit an alpha particle?

A)yes, because alpha particles are the simplest form of radiation
B)no, because it would require the nuclear fission of hydrogen, which is impossible
C)yes, but it does not occur very frequently
D)no, because it does not contain enough nucleons

Question 17

The alpha particle has twice the electric charge of the beta particle but deflects less than the beta in a magnetic field because it

A)moves much slower.
B)moves much faster.
C)has much more inertia.
D)has much less inertia.

Question 18

Which of the following provides the minimum amount of protection you need to block the following form of radiation? beta

A)lead suit
B)suntan lotion
C)thick leather
D)T-shirt
E)none of the above

Question 19

Alpha and beta rays are deflected in opposite directions in a magnetic field because

A)they have opposite charges.
B)they spin in opposite directions.
C)alpha particles contain nucleons and beta particles do not.
D)all of the above

Question 20

Why would you expect alpha particles to be less able to penetrate materials than beta particles of the same kinetic energy?

A)Alpha particles pick up electrons to become harmless helium atoms.
B)Alpha particles carry twice the electric charge.
C)Alpha particles move much slower for a given kinetic energy.
D)Two of the above answers are reasonable.

Question 21

A sample of radium is usually a little warmer than its surroundings because

A)it efficiently absorbs and releases energy from sunlight.
B)its atoms are continually being struck by alpha and beta particles.
C)it is radioactive.
D)it emits alpha and beta particles.

Question 22

Which of the following emits more radiation?

A)a coal-fired power plant
B)a nuclear power plant
C)fallout from nuclear tests in the '50s and '60s
D)a television set
E)a computer monitor

Question 23

Which of the following might be considered a viable application of a radioactive tracer?

A)adding a stream of radioisotopes to waste water to examine where pollution goes when it flows into the ocean
B)placing radioactive sources around a room to trace the location of people as they move through the room
C)embedding a radioactive plug in a valuable necklace so that its location can be determined using a Geiger counter
D)all of the above
E)none of the above

Question 24

In bombarding atomic nuclei with proton "bullets," the protons must be accelerated to high energies to make contact with the target nuclei

A)because the target nuclei are so small.
B)because the target nuclei are negatively charged.
C)in order to penetrate through the electrons that surround each target nucleus.
D)because the target nuclei are positively charged.

Question 25

Why are smaller nuclei such as carbon-14 often radioactive? (carbon-12 is the most common and most stable form of carbon.)

A)The attractive force of the nucleons has a limited range.
B)The isolated neutron is not stable and will undergo spontaneous transformation into a proton and an electron.
C)Hmmm... mysterious are the ways of the force.
D)both A and B
E)none of the above

Question 26

Which type of radiation from cosmic sources predominates on the inside of a high-flying commercial airplane: alpha, beta, or gamma?

A)alpha radiation
B)beta radiation
C)gamma radiation
D)None of these predominate as all three are abundant.

Question 27

Why is the combination of two protons and two neutrons stable, but two protons and one neutron is not?

A)There are not enough neutrons to overcome the electrical repulsion of the protons.
B)There are not enough neutrons to overcome the nuclear repulsion of the protons.
C)The nuclear attraction between protons is greater than that between neutrons.
D)The electrical repulsion between the two protons is greater in one case than the other.
E)none of the above

Question 28

Which of the following statements best describes why a large nucleus is more likely to undergo radioactive decay?

A)The nuclear forces are not as strong as the repulsive electrical forces between nucleons.
B)The nuclear force between the nucleons are very strong and squeeze out other nucleons.
C)The nucleon-nucleon attraction is stronger than the proton-proton repulsion.
D)The proton-proton repulsion cannot overcome the nucleon attraction.
E)All nuclei are equally likely to undergo radioactive decay.

Question 29

Which of the following statements best describes the strong nuclear force?

A)The force is very strong but has a very short range.
B)The electrical force is stronger than the nuclear force.
C)The force is very strong and works over very long distances.
D)The strength of the force increases with distance.
E)The force has two sides: the light side and the dark side.

Question 30

Which of the following types of radiation might be best for medical imaging?

A)Gamma radiation would be best because it penetrates the best.
B)Alpha radiation would be best because it penetrates the least and therefore does the least damage.
C)Beta radiation would be best because it can be measured electrically.
D)Only X-rays are used for medical imaging.
E)none of the above

Question 31

A friend produces a Geiger counter to check the local background radiation. It ticks. Another friend, who normally fears most that which is understood least, makes an effort to keep away from the region of the Geiger counter and looks to you for advice. What do you say?

A)Run away as fast as you can!
B)The Geiger counter is emitting radiation.
C)The Geiger counter is detecting naturally occurring radiation from your body.
D)Wear heavy clothes.

Question 32

Coal contains only minute quantities of radioactive materials, yet there is more environmental radiation surrounding a coal-fired power plant than a fission power plant. This indicates that

A)the coal-fired power plant's radiation shields need to be strengthened.
B)the coal-fired power plant has been contaminated.
C)the coal-fired power plant contains none of the radiation it releases.
D)the news media is biased in its coverage.

Question 33

The element uranium (U, atomic no. = 92)often has 146 (or more)neutrons but it will still undergo radioactive decay. Which statement might best describe why?

A)The attractive force of the nucleons has a limited range.
B)The isolated neutron is not stable and will undergo spontaneous transformation into a proton and an electron.
C)The force is strong with U, but tainted with the dark side it is.
D)both A and B
E)none of the above

Question 34

Which of the following statements best describes the role of neutrons in the nucleus?

A)The neutrons stabilize the nucleus by attracting other nucleons.
B)The neutrons stabilize the nucleus by forming bonds with other neutrons.
C)The neutrons stabilize the nucleus by attracting protons.
D)The neutrons stabilize the nucleus by balancing charge.
E)The neutrons stabilize the nucleus by adding mass.

Question 35

In the 19th century the famous physicist Lord Kelvin estimated the age of Earth to be much much less than its present estimate. What information did Kelvin not have to account for his error?

A)Lord Kelvin knew only classical physics and had no knowledge of anthropological dating.
B)Lord Kelvin had no knowledge of radio waves for measuring distance and age of planets since they have not yet been introduced into science.
C)Lord Kelvin was not aware of radioactive decay, a source of energy to keep Earth warm for billions of years.
D)Lord Kelvin never gave any estimate of the age of Earth.

Question 36

When food is irradiated with gamma rays from a cobalt-60 source, does the food become radioactive? Why?

A)Yes. This is why irradiation with cobalt-60 is no longer approved by the FDA.
B)Yes. However, the radioactivity resulting is well below the danger level established by the FDA.
C)No. The gamma rays do not have sufficient energy to initiate the nuclear reaction in the atoms of the food.
D)Yes and No. Although the gamma rays initiate the nuclear reaction the radioactivity does not show up until the food is ingested.

Question 37

If an atom has 104 electrons, 157 neutrons, and 104 protons, what is its approximate atomic mass?

A)The approximate atomic mass is 365.
B)The approximate atomic mass is 261.
C)The approximate atomic mass is 157.
D)The approximate atomic mass is cannot be determined with the information given.

Question 38

You and your friend journey to the mountain foothills to get closer to nature and escape such things as radioactivity. While bathing in the warmth of a natural hot spring she wonders aloud how the spring gets its heat. What do you tell her? You tell her that the hot water is the result of

A)industrial thermal pollution.
B)radioactivity.
C)chemical reactions involving the atomic nucleus.
D)nuclear fission.

Question 39

A pair of protons in an atomic nucleus repel each other, but they are also attracted to each other. Why?

A)The pair repel each other by nuclear force but attract one another by an electrical force.
B)The pair repel each other since they are both positively charges but they are held together by much stronger forces known as quarks.
C)The pair attract each other by nuclear force but also repel one another by a weaker electrical force.
D)Although it is known that protons repel each other at short distances because of like charge, it is not known what actually holds protons together in the nucleus because we have never seen the nucleus of an atom.

Question 40

Just after an alpha particle leaves the nucleus, would you expect it to speed up? Why?

A)No. Once the alpha particle leaves the nucleus it is slowed by the repulsion of the next closest atom's nucleus.
B)No. As the alpha particle leaves the nucleus it is slowed by the constant attraction of the electrons surrounding the nucleus.
C)Yes. Once the alpha particle leaves the nucleus there are no more forces acting on it and it therefore accelerates.
D)Yes. Once the alpha particle leaves the nucleus it accelerates because of mutual electric repulsion with the nucleus from which it escaped.

Question 41

Which of the following nuclear equations correctly describes beta emission?

A) Th → Pa + e
B) Th → Ac + e
C) Th → Pa + e
D) Th → e
E)none of the above

Question 42

What is a half-life?

A)It is the time it takes for 1/2 of the material to undergo radiodecay.
B)It is the time needed until 1/2 of the radiation is gone.
C)It is the time it takes for 1/2 of the material to decompose.
D)It is half of the lifetime of the radioactivity in a sample.
E)all of the above

Question 43

If three samples have the half-lives listed below, which sample would remain radioactive the longest?

A)a sample with a half-life of 20 minutes
B)a sample with a half-life of 20 hours
C)a sample with a half-life of 20 years
D)a sample with a half-life of 20 million years
E)none of the above

Question 44

What is transmutation?

A)changing one element into another by adding or removing protons from the nucleus
B)changing one element into another by adding or removing electrons from the nucleus
C)changing one element into another by adding or removing neutrons from the nucleus
D)a process that emits radiation
E)alteration in DNA due to radioactivity

Question 45

Which of the following nuclear equations correctly describes beta emission?

A) U → Th + He
B) U → U + He
C) U → Pu + He
D) U → He
E)none of the above

Question 46

Which of the following nuclear equations correctly describes alpha emission?

A) U → Th + He
B) U → U + He
C) U → Pu + He
D) U → He
E)none of the above

Question 47

What evidence supports the contention that the strong nuclear force is stronger than the electrical interaction at short inter-nuclear distances?

A)Protons are able to exist side-by-side within an atomic nucleus.
B)Neutrons spontaneously decay into protons and electrons.
C)Uranium deposits are always slightly warmer than their immediate surroundings.
D)The radio interference that arises adjacent to any radioactive source.

Question 48

Complete the following nuclear equation: ?? → At + e

A) Ra
B) At
C) Po
D) Rn
E)none of the above

Question 49

Complete the following nuclear equation: Bi → Tl + ??

A) e
B) He
C)gamma ray
D)both A and B
E)none of the above

Question 50

Complete the following nuclear equation: Tl → Pb + ??

A) e
B) He
C)gamma ray
D)both A and B
E)none of the above

Question 51

Complete the following nuclear equation: Po → ?? + He

A) Po
B) Pb
C) Pb
D) Rn
E)none of the above

Question 52

Your friend says that the helium used to inflate balloons is a product of radioactive decay. Another friend says no way. With whom do you agree?

A)If helium were a product of radioactive decay, we would all be radioactive. Agree with the friend that says "no way."
B)Radioactive decay produces alpha particles, not helium. Agree with the friend that says "no way."
C)Your first friend is correct. Radioactive isotopes emit alpha particles which, in turn, capture electrons and become helium atoms.
D)Helium is an element of the periodic table, not some product of any reaction. Agree with the friend that says "no way."

Question 53

Which type of radiation is being emitted in the following incomplete nuclear equation: Po → Pb + ??

A)alpha
B)beta
C)gamma
D)A and B
E)none of the above

Question 54

Complete the following nuclear equation: ?? → Rn + He

A) Ra
B) At
C) Po
D) Rn
E)none of the above

Question 55

If a material has a half-life of 24 hours, how long do you have to wait until the amount of radioisotope is 1/4 its original amount?

A)12 hours
B)24 hours
C)48 hours
D)72 hours
E)practically forever, but it may be safe by then

Question 56

If three samples have the half-lives listed below, which is the most radioactive?

A)a sample with a half-life of 20 minutes
B)a sample with a half-life of 20 hours
C)a sample with a half-life of 20 years
D)a sample with a half-life of 20 million years
E)none of the above

Question 57

Complete the following nuclear equation: Bi → ?? + e

A) Po
B) Pb
C) Pb
D) Th
E)none of the above

Question 58

What property of half-lives makes radioactive material so problematic?

A)There is no known way to shorten a half-life.
B)Radioactivity is limited by the natural decay-time to stable isotopes.
C)All half-lives are long.
D)There is no known way to measure half-lives with any accuracy.
E)both A and B

Question 59

Which type of radiation is being emitted in the following incomplete nuclear equation: Pb → Bi + ??

A)alpha
B)beta
C)gamma
D)A and B
E)none of the above

Question 60

Which of the following nuclear equations correctly describes alpha emission?

A) Th → Pa + e
B) Th → Ac + e
C) Th → Pa + e
D) Th → e
E)none of the above

Question 61

Why wouldn't you use carbon-14 dating on a piece of shell that was estimated to be 1 million years old?

A)Sea shells do not have radioisotopes.
B)Carbon dating is only useful on plants.
C)Uranium dating is better for items older than 1/2 million years.
D)Carbon dating can only be used on items that were once alive.
E)The amount of radioactive carbon in the sample would probably too small to measure.

Question 62

When Ra decays by emitting an alpha particle, what is the atomic number of the resulting nucleus? What is the resulting atomic mass?

A)atomic number = 86; atomic mass = 222
B)atomic number = 87; atomic mass = 226
C)atomic number = 86; atomic mass = 224
D)atomic number = 87; atomic mass = 224

Question 63

Which type of radiation-alpha, beta, or gamma-results in the greatest change in atomic mass number?

A)alpha radiation
B)beta radiation
C)gamma radiation
D)They all result in the same change in atomic mass number.

Question 64

If carbon-14 is a beta emitter, what is the likely product of radioactive decay?

A)nitrogen-14
B)carbon-12
C)oxygen-18
D)berrylium-10
E)none of the above

Question 65

If Uranium-234 decays via alpha emission, what is the likely product of radioactive decay? (U, atomic no. = 92)

A) Th
B) Np
C) Th
D) Np
E)none of the above

Question 66

How come an animal's carbon-14 levels do not start to decrease until it dies?

A)because it constantly replenishes its carbon-14 supply by eating plants with carbon-14 in them
B)because it constantly replenishes its carbon-14 supply by breathing air with carbon-14 in it
C)because it is constantly being bombarded with cosmic rays
D)carbon-14 only starts to decay after the animal dies
E)the carbon-14 levels do not decrease because the carbon-13 in its skin protects it from cosmic rays

Question 67

Elements above uranium in the periodic table do not exist in any appreciable amounts in nature because they have short half-lives. Yet there are several elements below uranium in atomic number with equally short half-lives that do exist in appreciable amounts in nature. How can you account for this?

A)These are isotopes formed by living bodies.
B)These isotopes were placed in nature by the testing of nuclear bombs.
C)These isotopes were formed from the fusion of even smaller isotopes.
D)These isotopes result from the radioactive decay of uranium.

Question 68

When the isotope bismuth-213 emits an alpha particle, what new element results?

A)lead
B)platinum
C)polonium
D)thallium

Question 69

How is it possible for an element to decay "forward in the periodic table"--that is, to decay to an element of higher atomic number?

A)When the decay is instigated by a collision with a proton.
B)As a beta particle is released, a neutron transforms into a proton.
C)This only occurs during nuclear fusion.
D)It is not possible. Radioactive decay always results in an isotope with the same or lower atomic number.

Question 70

How can a half-life be used to tell the age of a sample?

A)The half-life of an isotope is constant.
B)The amount of radioactive form depends on the amount of radiation in the surroundings.
C)The ratio between the radioactive form and the stable form depends on the archaeological record.
D)The ratio between the radioactive form and stable form varies regularly with time.
E)both C and D

Question 71

The half-life of carbon-14 is 5,730 years. A sample is found to have one-eighth the original amount of carbon-14 in it. How old is the sample?

A)5,730 years
B)716 years
C)4,5800 years
D)17,200 years
E)none of the above

Question 72

Why is the carbon-14 dating not accurate for estimating the age of materials more than 50,000 years old?

A)This form of radioactive dating is only accurate back 1,400 years.
B)The concentration of carbon-14 in a body after 50,000 years is too low.
C)Living organisms are too decomposed after 50,000 years.
D)Actually, carbon-14 dating is accurate back to around 5 million years ago.

Question 73

How many alpha particles are emitted in the series of radioactive decay events from a U-238 nucleus to a Pb-206 nucleus?

A)32
B)16
C)8
D)4

Question 74

The age of the Dead Sea Scrolls was found by carbon-14 dating. Could this technique have worked if they were carved in stone tablets? Explain.

A)Yes, because there are appreciable levels of carbon even in stone.
B)No, this method of dating requires a material that was once living.
C)Yes, because X-ray images could be collected instead.
D)No, the stones in the arid environment of the Dead Sea would have lost all of their carbon-14 by now.

Question 75

Which type of radiation-alpha, beta, or gamma-results in the least change in atomic number?

A)alpha radiation
B)beta radiation
C)gamma radiation
D)They all result in the same change in atomic mass number.

Question 76

When Po emits a beta particle, it transforms into a new element. What are the atomic number and atomic mass of this new element?

A)atomic number = 84; atomic mass = 219
B)atomic number = 86; atomic mass = 214
C)atomic number = 85; atomic mass = 218
D)atomic number = 82; atomic mass = 214

Question 77

Radium-226 is a common isotope on Earth, but has a half-life of about 1600 years. Given that Earth is some 5 billions years old, why is there any radium at all?

A)Radium-226 is one of several self-transmutating isotopes of the elements of the periodic table and is able to replenish itself so that it is never depleted.
B)Radium-226 and Radium-218 undergo a series of transmutation reactions of alpha and beta decay to repeatedly become one another approximately every 1600 years.
C)Radium-226 is a "daughter" isotope and the result of the radioactive decay of uranium.
D)Radium-226 and Astatine-218 are converted back and forth via transmutation to one another at each of their respective half-life cycles.

Question 78

A certain radioactive element has a half-life of one hour. If you start with a 1-g sample of the element at noon, how much of this same element will be left at 3:00 PM?

A)0.5 gram
B)0.25 gram
C)0.125 gram
D)0.0625 gram

Question 79

If a nucleus of Th absorbs a neutron and the resulting nucleus undergoes two successive beta decays (emitting electrons), what nucleus results?

A)americium-232
B)plutonium-232
C)thorium-233
D)uranium-233

Question 80

Which of the following statements about carbon-14 dating is true?

A)Carbon-14 dating is very accurate because the amount of carbon-14 in the atmosphere is constant.
B)Carbon-14 can be used to date anything younger than 50,000 years.
C)Carbon-14 dating can be used to date stone tools as well as bone.
D)all of the above
E)none of the above