Question 1

Which of the following elements is the most stable from a nuclear point of view?

Accepted Answer

A) iron 
B) hydrogen 
C) argon 
D) uranium 
E) All are equally stable.

Question 2

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

Accepted Answer

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 3

What is a rem?

Accepted Answer

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 4

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

Accepted Answer

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 5

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

Accepted Answer

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

Question 6

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

Accepted Answer

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 7

If a fusion reaction produces no appreciable radioactive isotopes, why does a hydrogen bomb produce significant radioactive fallout?

Accepted Answer

A) The fallout is only the radioactive remnants of the bomb's structure and casing. 
B) It is a misconception that fusion reactions produce no appreciable radioactive isotopes. Therefore, radioactive fallout is unavoidable. 
C) The radioactive fallout is a result of the fission reaction used to ignite the thermonuclear fusion reaction. 
D) Once a hydrogen bomb is exploded, all matter within nearly 100 miles becomes radioactive fallout.

Question 8

Uranium-235 releases an average of 2.5 neutrons per fission, while plutonium-239 releases an average of 2.7 neutrons per fission. Which of these elements might you therefore expect to have the smaller critical mass?

Accepted Answer

A) plutonium-239 
B) uranium-235 
C) The number of neutrons per fission will not effect the size of critical mass. 
D) The critical mass of these elements cannot be determined from only the number of neutrons per fission.

Question 9

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?

Accepted Answer

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 10

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

Accepted Answer

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

Question 11

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?

Accepted Answer

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 12

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

Accepted Answer

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 13

Which of the following statements about fission is true?

Accepted Answer

A) The amount of energy released in the fission of large nuclei is very large. 
B) The amount of energy released in the fusion of small nuclei is very large. 
C) Bombarding a nucleus with neutrons always leads to fission. 
D) The fragments of a fusion reaction are always the same size. 
E) none of the above

Question 14

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

Accepted Answer

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 15

Which of the following statements regarding a nucleon is true in regards to nuclear reactions?

Accepted Answer

A) A nucleon inside a nucleus has a lower mass than a nucleon outside of the nucleus. 
B) The number of nucleons changes in a nuclear reaction, therefore the mass changes. 
C) A nucleon has a higher energy inside a nucleus, and releases it when it undergoes nuclear reactions. 
D) A nucleon's mass is constant. 
E) A nucleon is more stable outside the nucleus.

Question 16

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

Accepted Answer

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

Question 17

Is the mass of an atomic nucleus greater or less than the sum of the masses of the nucleons composing it? Why don't the nucleon masses add up to the total nuclear mass?

Accepted Answer

A) Greater. We need to add the masses of the surrounding electrons to the masses of the nucleons. 
B) Neither. The mass of the atomic nucleus is exactly the sum of the masses of the nucleons. 
C) Less. The individual nucleons have greater mass when separated from the nucleus. This additional mass is a result of the energy of separation. 
D) Greater. The mass of the atomic nucleus also has mass of the "atomic glue" that holds the nucleons together in the nucleus.

Question 18

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

Accepted Answer

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 19

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

Accepted Answer

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 20

Which of the following statements regarding a nucleon is true?

Accepted Answer

A) Attraction between nucleons changes their mass. 
B) The mass of a nucleon depends on which nucleus it is in. 
C) Some of the mass of a nucleon can be converted into energy by breaking certain nuclei. 
D) both A and C 
E) all of the above

Exam 13: The Atomic Nucleus and Radioactivity