Question 1

The radioactive isotope ¹⁴C beta- decays to the daughter nucleus A) "¹³C." B) "¹³N." C) "¹⁵C." D) "¹⁴N." E) "None of the above."

Accepted Answer

In beta decay, a neutron in the nucleus is converted into a proton, emitting a beta particle (electron) and an antineutrino. This increases the atomic number by 1, turning carbon-14 into nitrogen-14.

Question 2

In a nuclear accident such as occurred at Chernobyl, the long- term biological damage is caused by
A) nuclear fission occurring within the biological cells.
B) alpha, beta, and gamma particles passing through biological cells.
C) the thermal energy produced by radioactive decay within biological cells.
D) the high energy vibrations of the water molecule that are caused by radioactive isotopes.
E) nuclear fusion occurring within the biological cells.

Accepted Answer

The long-term biological damage from a nuclear accident is primarily due to the ionizing radiation from alpha, beta, and gamma particles, which can damage or alter the DNA and other critical molecules within biological cells.

Question 3

Radon is
A) the radioactive substance that will probably be used to irradiate and sterilize food.
B) the main component in the radioactive fallout from nuclear weapons and nuclear power plant accidents.
C) a type of electromagnetic radiation that is produced by the sun and partially penetrates Earth's atmosphere.
D) a radioactive gas produced by the rocks and soil that can filter into houses.
E) the chemically active element in asbestos.

Accepted Answer

Radon is a naturally occurring radioactive gas that is produced by the decay of uranium in rocks and soil. It can seep into homes through cracks in floors and walls.

Question 4

¹²C and ¹³C differ in their A) number of neutrons. B) chemical behavior. C) number of protons. D) number of electrons in orbit around the nucleus. E) All of the above.

Accepted Answer

^12C and ^13C are isotopes of carbon, differing only in the number of neutrons. ^12C has 6 neutrons, while ^13C has 7 neutrons. They have the same number of protons and electrons, which means their chemical behavior is nearly identical.

Question 5

According to most scientists, when did the first hominids-- direct human forbears that were fully separated from the apes-- appear on Earth?
A) about a billion years ago
B) a few billion years ago
C) a few million years ago
D) a few thousand years ago
E) about 100 billion years ago

Accepted Answer

The first hominids, which are direct human ancestors, appeared a few million years ago, with evidence suggesting they emerged around 6 to 7 million years ago.

Question 6

At Chernobyl, one of the harmful radioactive isotopes was ¹³¹I, a beta emitter with a halflife of 8 days. Suppose some of this isotope is deposited on a field. What can we say about this field 40 days later? A) Its radioactivity level has decreased to 1/32 of its original level. B) Its radioactivity level has decreased to 1/64-- one sixty- forth-- of its original level. C) Its radioactivity has decreased to harmless levels. D) Its radioactivity level has decreased to 1/16 of its original level. E) It is just as radioactive as it was to begin with.

Accepted Answer

The half-life of I-131 is 8 days. After 40 days, which is 5 half-lives (40/8), the radioactivity level decreases to (1/2)^5 = 1/32 of its original level.

Question 7

Which of the following is classified as "ionizing radiation"?
A) alpha and beta radiation
B) gamma rays
C) Both of the above.
D) X-rays
E) All of the above.

Accepted Answer

Ionizing radiation includes alpha and beta radiation, gamma rays, and X-rays, as they all have enough energy to remove tightly bound electrons from atoms, thus ionizing them.

Question 8

Of the four fundamental forces that act in the universe, which one supports a book that is at rest on a table?
A) the gravitational force
B) the photon force
C) the perpendicular force
D) the strong nuclear force
E) the electromagnetic force

Accepted Answer

The answer of Of the four fundamental forces that act...

Question 9

The carbon in a certain ancient ax- handle is only 1/8-- one- eighth-- as radioactive as the carbon in living wood. The half- life of ¹⁴C is 6000 years. From these facts we can conclude that A) the ax- handle is about 48,000 years old. B) the ax- handle is about 12,000 years old. C) the ax- handle was made from an unusual type of wood that was less radioactive than normal wood. D) the ax- handle is about 18,000 years old. E) the natural carbon- radioactivity at the time the ax- handle was made was only one- eighth of what it is today.

Accepted Answer

The ax-handle is 1/8 as radioactive, which means it has gone through 3 half-lives (since (1/2)^3 = 1/8). Each half-life is 6000 years, so 3 half-lives is 18,000 years.

Question 10

Radioactive dating methods and other dating methods indicate that hominids have been on Earth for about
A) 5 billion years.
B) 5000 years.
C) 5 million years.
D) 15 billion years.
E) 100,000 years.

Accepted Answer

Radioactive dating and other methods suggest that hominids have been on Earth for approximately 5 million years, which aligns with the fossil record of early human ancestors.

Question 11

Which of the following is not one of the four fundamental forces in nature?
A) frictional force
B) weak nuclear force
C) gravitational force
D) strong nuclear force
E) electromagnetic force

Accepted Answer

Frictional force is not one of the four fundamental forces in nature. The four fundamental forces are the weak nuclear force, the gravitational force, the strong nuclear force, and the electromagnetic force.

Question 12

In every nuclear reaction,
A) nuclear structure is altered.
B) molecules combine with other molecules.
C) electrons combine with each other.
D) a nucleus is split.
E) nuclei are brought together and permanently combined with other nuclei.

Accepted Answer

In every nuclear reaction, the nuclear structure is altered, as it involves changes in the composition or energy state of an atomic nucleus.

Question 13

The graph above shows the decay curve for a certain radioactive substance. The half- life of this substance is approximately
A) 0.5 days.
B) 2 days.
C) 1.5 days.
D) 1 day.
E) 3 days.

Accepted Answer

The answer of  The graph above shows the decay...

Question 14

Suppose that Al the physicist observes a single radioactive nucleus. The length of time until that particular nucleus decays is
A) unpredictable because of fundamental uncertainties arising from quantum physics
B) predictable, provided Al knows the precise nuclear state of this nucleus.
C) predictable from the known half- life of the nucleus.
D) unpredictable because of the practical difficulties of obtaining all the information needed to make the prediction.
E) unpredictable because of fundamental uncertainties arising from Newtonian physics.

Accepted Answer

The decay of a single radioactive nucleus is a random process governed by quantum mechanics, making it fundamentally unpredictable.

Question 15

Suppose that a certain saber- toothed- tiger contained one gram of ¹⁴C [half- life 6000 years] when it died. The approximate ¹⁴C content of the remains of this tiger 24,000 years later would be A) zero grams. B) 1/32 gram. C) 1/16 gram. D) 1/8 gram. E) impossible to predict.

Accepted Answer

The answer of Suppose that a certain saber- toothed- tiger...

Question 16

We cannot predict the precise decay time of a particular radioactive ¹⁴C nucleus because A) of the quantum entanglement of its protons and neutrons. B) a single nucleus is too small to be seen or directly detected. C) of quantum uncertainties. D) the calculation is too difficult for today's computers. E) of the difficulty of determining the precise initial states of all its protons and neutron.

Accepted Answer

Radioactive decay is a quantum process, and the exact time at which a particular nucleus will decay is inherently uncertain due to the probabilistic nature of quantum mechanics.

Question 17

Two different isotopes of the same element have
A) the same chemical properties, but different properties in nuclear processes.
B) different chemical properties, but the same properties in nuclear processes.
C) the same chemical properties, and also the same properties in nuclear processes.
D) different chemical properties, and also different properties in nuclear processes.
E) None of the above.

Accepted Answer

Isotopes of the same element have the same number of protons and electrons, which determine chemical properties, but differ in the number of neutrons, affecting nuclear properties.

Quiz 14: The Nucleus and Radioactivity: an New Force

The radioactive isotope 14 C beta- decays to the daughter nucleus

In a nuclear accident such as occurred at Chernobyl, the long- term biological damage is caused by

Radon is

12C and 13C differ in their

According to most scientists, when did the first hominids-- direct human forbears that were fully separated from the apes-- appear on Earth?

At Chernobyl, one of the harmful radioactive isotopes was 131I, a beta emitter with a halflife of 8 days. Suppose some of this isotope is deposited on a field. What can we say about this field 40 days later?

Which of the following is classified as "ionizing radiation"?

Of the four fundamental forces that act in the universe, which one supports a book that is at rest on a table?

The carbon in a certain ancient ax- handle is only 1/8-- one- eighth-- as radioactive as the carbon in living wood. The half- life of 14C is 6000 years. From these facts we can conclude that

Radioactive dating methods and other dating methods indicate that hominids have been on Earth for about

Which of the following is not one of the four fundamental forces in nature?

In every nuclear reaction,

The graph above shows the decay curve for a certain radioactive substance. The half- life of this substance is approximately

Suppose that Al the physicist observes a single radioactive nucleus. The length of time until that particular nucleus decays is

Suppose that a certain saber- toothed- tiger contained one gram of 14C [half- life 6000 years] when it died. The approximate 14C content of the remains of this tiger 24,000 years later would be

We cannot predict the precise decay time of a particular radioactive 14C nucleus because

Two different isotopes of the same element have

The radioactive isotope ¹⁴C beta- decays to the daughter nucleus

¹²C and ¹³C differ in their

At Chernobyl, one of the harmful radioactive isotopes was ¹³¹I, a beta emitter with a halflife of 8 days. Suppose some of this isotope is deposited on a field. What can we say about this field 40 days later?

The carbon in a certain ancient ax- handle is only 1/8-- one- eighth-- as radioactive as the carbon in living wood. The half- life of ¹⁴C is 6000 years. From these facts we can conclude that

Suppose that a certain saber- toothed- tiger contained one gram of ¹⁴C [half- life 6000 years] when it died. The approximate ¹⁴C content of the remains of this tiger 24,000 years later would be

We cannot predict the precise decay time of a particular radioactive ¹⁴C nucleus because