Chapter 33: Atomic Nucleus And Radioactivity
Questions and Answers
- 1.
X-rays may be regarded as
- A.
High frequency sound waves.
- B.
High frequency radio waves.
- C.
Both of these
- D.
None of these
Correct Answer
B. High frequency radio waves.Explanation
X-rays cannot be regarded as high frequency sound waves because sound waves are mechanical waves that require a medium to travel, while X-rays are electromagnetic waves that can travel through a vacuum. X-rays also cannot be considered high frequency radio waves because radio waves have much lower frequencies than X-rays. Therefore, the correct answer is none of these options.Rate this question:
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- 2.
X-rays are similar to
- A.
Alpha rays.
- B.
Beta rays.
- C.
Gamma rays.
- D.
All of these
- E.
None of these
Correct Answer
C. Gamma rays.Explanation
X-rays are similar to gamma rays. Both X-rays and gamma rays are forms of electromagnetic radiation with high energy and short wavelengths. They are both ionizing radiation, meaning they have the ability to remove electrons from atoms and can therefore cause damage to living tissue. X-rays and gamma rays are used in similar applications, such as medical imaging and radiation therapy. Therefore, the correct answer is gamma rays.Rate this question:
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- 3.
Which radiation has no electric charge associated with it?
- A.
Alpha rays
- B.
Beta rays
- C.
Gamma rays
- D.
All of these
- E.
None of these
Correct Answer
C. Gamma raysExplanation
Gamma rays have no electric charge associated with them. Unlike alpha and beta rays, which consist of charged particles (alpha particles are positively charged helium nuclei, and beta particles are either electrons or positrons), gamma rays are a form of electromagnetic radiation and do not carry any electric charge. Therefore, the correct answer is gamma rays.Rate this question:
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- 4.
Both X-rays and gamma rays are emitted from
- A.
Different parts of the atom.
- B.
A variety of certain atomic nuclei.
Correct Answer
A. Different parts of the atom.Explanation
X-rays and gamma rays are both forms of electromagnetic radiation that are emitted from different parts of the atom. X-rays are produced when high-energy electrons collide with atoms, causing the electrons to be ejected from their inner orbits. This creates a gap in the electron cloud, and when an electron from an outer orbit fills this gap, it releases energy in the form of an X-ray photon. Gamma rays, on the other hand, are emitted from the nucleus of an atom during radioactive decay or nuclear reactions. They are highly energetic and have the shortest wavelength and highest frequency among all forms of electromagnetic radiation.Rate this question:
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- 5.
The sources of X-rays and gamma rays, respectively, are
- A.
Electron clouds and the atomic nucleus.
- B.
The atomic nucleus and electron clouds.
- C.
Both electron clouds.
- D.
Both the atomic nucleus.
- E.
None of these
Correct Answer
A. Electron clouds and the atomic nucleus.Explanation
X-rays and gamma rays are both forms of electromagnetic radiation. X-rays are produced when high-energy electrons collide with atoms, causing the electrons to be knocked out of their orbits and creating X-ray photons. This process primarily occurs in the electron clouds surrounding the atomic nucleus. On the other hand, gamma rays are generated through nuclear processes, such as radioactive decay or nuclear reactions. These processes involve the atomic nucleus directly. Therefore, the correct answer is that X-rays are produced in the electron clouds and gamma rays are produced in the atomic nucleus.Rate this question:
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- 6.
A nucleon is either
- A.
A positron or an electron.
- B.
A proton or an electron.
- C.
A neutron or an electron.
- D.
A proton or a neutron.
Correct Answer
D. A proton or a neutron.Explanation
A nucleon is a term used to describe the particles found in the nucleus of an atom, which are either protons or neutrons. Protons have a positive charge, while neutrons have no charge. Electrons, on the other hand, are found in the electron cloud surrounding the nucleus, not in the nucleus itself. Therefore, the correct answer is that a nucleon is either a proton or a neutron.Rate this question:
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- 7.
The mass of an atomic nucleon is nearly
- A.
Twice the mass of an electron.
- B.
Four times the mass of an electron.
- C.
A thousand times the mass of an electron.
- D.
Two thousand times the mass of an electron.
Correct Answer
D. Two thousand times the mass of an electron.Explanation
The mass of an atomic nucleon refers to the mass of a proton or a neutron. Compared to an electron, the mass of an atomic nucleon is much larger. The answer choice "two thousand times the mass of an electron" accurately reflects this significant difference in mass between an atomic nucleon and an electron.Rate this question:
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- 8.
Once an alpha particle is outside the nucleus it is
- A.
Free to wander about the nucleus.
- B.
Quickly bound to a neighboring nucleus.
- C.
Electrostatically repelled.
- D.
Radioactive.
Correct Answer
C. Electrostatically repelled.Explanation
Once an alpha particle is outside the nucleus, it experiences electrostatic repulsion due to the positive charge of the alpha particle and the positive charge of the nucleus. This repulsion causes the alpha particle to be pushed away from the nucleus and prevents it from freely wandering about or quickly binding to a neighboring nucleus. The alpha particle is not radioactive itself, but it is emitted during certain radioactive decay processes.Rate this question:
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- 9.
When a nucleus emits a beta particle, its atomic number
- A.
Remains constant, but its mass number changes.
- B.
Remains constant, and so does its mass number.
- C.
Changes, but its mass number remains constant.
- D.
Changes, and so does its mass number.
- E.
None of these
Correct Answer
C. Changes, but its mass number remains constant.Explanation
When a nucleus emits a beta particle, it undergoes a process called beta decay. In beta decay, a neutron in the nucleus is converted into a proton, and a beta particle (an electron or a positron) is emitted. Since the number of protons determines the atomic number of an atom, the atomic number changes when a beta particle is emitted. However, the mass number, which is the total number of protons and neutrons in the nucleus, remains constant because the number of neutrons is converted into protons. Therefore, the correct answer is that the atomic number changes, but the mass number remains constant.Rate this question:
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- 10.
A quark is
- A.
An elementary particle.
- B.
A building block of nucleons.
- C.
A building block of hadrons.
- D.
All of these
- E.
None of these
Correct Answer
D. All of theseExplanation
The correct answer is "all of these" because a quark is an elementary particle, meaning it is a fundamental particle that cannot be broken down into smaller particles. It is also a building block of nucleons, which are the particles that make up atomic nuclei, and it is a building block of hadrons, which are particles composed of quarks. Therefore, a quark satisfies all the given statements, making "all of these" the correct answer.Rate this question:
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- 11.
An atom with an imbalance of electrons to protons is
- A.
A hadron.
- B.
A baryon.
- C.
An ion.
- D.
An isotope.
- E.
None of these
Correct Answer
C. An ion.Explanation
An atom with an imbalance of electrons to protons is an ion. When an atom gains or loses electrons, it becomes charged and forms an ion. The number of protons in an atom determines its atomic number and element, while the number of electrons determines its charge. If an atom gains electrons, it becomes negatively charged (anion), and if it loses electrons, it becomes positively charged (cation). Therefore, an atom with an imbalance of electrons to protons is an ion.Rate this question:
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- 12.
The atomic number of an element is the same as the number of its
- A.
Protons.
- B.
Neutrons.
- C.
Nucleons.
- D.
Neither of these
Correct Answer
A. Protons.Explanation
The atomic number of an element corresponds to the number of protons in its nucleus. Protons are positively charged particles found in the nucleus of an atom. Neutrons, on the other hand, have no charge, and nucleons refer to both protons and neutrons combined. Therefore, the correct answer is protons.Rate this question:
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- 13.
The atomic mass number of an element is the same as the number of its
- A.
Protons.
- B.
Neutrons.
- C.
Nucleons.
- D.
None of these
Correct Answer
C. Nucleons.Explanation
The atomic mass number of an element represents the total number of nucleons in its nucleus, which includes both protons and neutrons. Protons have a positive charge and are found in the nucleus, while neutrons have no charge and are also located in the nucleus. Therefore, the correct answer is nucleons, as it encompasses both protons and neutrons.Rate this question:
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- 14.
Deuterium and tritium are both
- A.
Forms of hydrogen.
- B.
Isotopes of the same element.
- C.
Both of these
- D.
Neither of these
Correct Answer
C. Both of theseExplanation
Deuterium and tritium are both forms of hydrogen. Deuterium is an isotope of hydrogen with one neutron and one proton, while tritium is an isotope of hydrogen with two neutrons and one proton. Therefore, both deuterium and tritium are different forms of hydrogen, making the answer "both of these" correct.Rate this question:
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- 15.
Different isotopes of an element have different numbers of
- A.
Protons.
- B.
Hadrons.
- C.
Photons.
- D.
Neutrons.
- E.
None of these
Correct Answer
D. Neutrons.Explanation
Different isotopes of an element have different numbers of neutrons. Isotopes are variants of an element that have the same number of protons but different numbers of neutrons. The number of protons determines the element's identity, while the number of neutrons affects its atomic mass. Therefore, the correct answer is neutrons.Rate this question:
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- 16.
Electric forces within an atomic nucleus tend to
- A.
Hold it together.
- B.
Push it apart.
- C.
Neither of these
Correct Answer
B. Push it apart.Explanation
The correct answer is "push it apart." This is because electric forces within an atomic nucleus are repulsive in nature. Protons, which are positively charged, experience a repulsive force from each other due to their like charges. This repulsion tends to push the protons apart, making it difficult to maintain the stability of the nucleus. However, the strong nuclear force counteracts this repulsion and holds the nucleus together.Rate this question:
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- 17.
Generally speaking, the larger a nucleus is, the greater its
- A.
Stability.
- B.
Instability.
- C.
Neither stability nor instability
Correct Answer
B. Instability.Explanation
The larger a nucleus is, the greater its instability. This is because as the nucleus increases in size, the number of protons and neutrons also increases. This leads to a stronger repulsive force between the positively charged protons, making the nucleus less stable. Additionally, larger nuclei tend to have a higher neutron-to-proton ratio, which can also contribute to instability. Therefore, larger nuclei are generally more prone to decay or undergo nuclear reactions, indicating their instability.Rate this question:
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- 18.
The half-life of an isotope is one day. At the end of two days the amount that remains is
- A.
None.
- B.
One-half.
- C.
One-quarter.
- D.
One-eighth.
- E.
None of these
Correct Answer
C. One-quarter.Explanation
The half-life of an isotope is the amount of time it takes for half of the sample to decay. In this case, since the half-life is one day, after two days, two half-lives have passed. This means that the original sample has been halved twice, resulting in one-quarter of the original amount remaining.Rate this question:
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- 19.
The half-life on an isotope is one day. At the end of three days, how much of the isotope remains?
- A.
None
- B.
One-half
- C.
One-quarter
- D.
One-eighth
- E.
None of these
Correct Answer
D. One-eighthExplanation
The half-life of an isotope is the time it takes for half of the initial amount of the isotope to decay. In this case, since the half-life is one day, after the first day, half of the isotope would remain. After the second day, half of that remaining amount would decay, leaving one-fourth of the initial amount. Finally, after the third day, half of that remaining amount would decay, leaving one-eighth of the initial amount. Therefore, the correct answer is one-eighth.Rate this question:
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- 20.
The half-life of a radioactive substance is INDEPENDENT of
- A.
The number (if large enough) of atoms in the substance.
- B.
Whether the substance exists in an elementary state or in a compound.
- C.
The temperature of the substance.
- D.
The age of the substance.
- E.
All of these
Correct Answer
E. All of theseExplanation
The half-life of a radioactive substance is a constant value that represents the time it takes for half of the substance to decay. This value is independent of the number of atoms in the substance because the decay process is based on the probability of individual atoms decaying, not the total number of atoms present. The half-life is also independent of whether the substance exists in an elementary state or in a compound because the decay process is determined by the specific radioactive isotope, not the chemical form of the substance. The temperature of the substance does not affect the half-life because it is a nuclear process, not a chemical reaction. Finally, the age of the substance does not impact the half-life because it is a characteristic property of the specific radioactive isotope.Rate this question:
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- 21.
The operation of a cloud chamber relies on
- A.
Magnetization.
- B.
Evaporation.
- C.
Acceleration.
- D.
Polarization.
- E.
Condensation.
Correct Answer
E. Condensation.Explanation
A cloud chamber is a device used to visualize the paths of charged particles by creating a supersaturated vapor. When a charged particle passes through the chamber, it ionizes the vapor, creating a trail of droplets. These droplets then condense around ions and form a visible track, allowing the path of the particle to be observed. Therefore, the operation of a cloud chamber relies on condensation, as it is the process by which the vapor forms visible droplets.Rate this question:
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- 22.
When an element undergoes nuclear transmutation, the result is a completely different
- A.
Isotope of the same element.
- B.
Ion of the same element.
- C.
Element.
Correct Answer
C. Element.Explanation
When an element undergoes nuclear transmutation, it means that its nucleus is changing, resulting in the formation of a different isotope of the same element. Isotopes are atoms of the same element that have different numbers of neutrons in their nucleus, but the same number of protons. Therefore, the correct answer is "isotope of the same element."Rate this question:
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- 23.
When an alpha particle is ejected from a nucleus, the nucleus then has less
- A.
Mass.
- B.
Charge.
- C.
Both of these
- D.
Neither of these
Correct Answer
C. Both of theseExplanation
When an alpha particle is ejected from a nucleus, it carries away both mass and charge. An alpha particle consists of two protons and two neutrons, so when it is emitted, the nucleus loses both mass and positive charge. Therefore, the correct answer is both of these.Rate this question:
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- 24.
When a beta particle is ejected from a nucleus, the nucleus then has a greater
- A.
Mass.
- B.
Charge.
- C.
Both of these
- D.
Neither of these
Correct Answer
B. Charge.Explanation
When a beta particle is ejected from a nucleus, it carries a negative charge. As a result, the nucleus loses one of its protons, which are positively charged particles. Since the number of protons determines the charge of an atomic nucleus, the ejection of a beta particle leads to a decrease in the overall positive charge of the nucleus. Therefore, the correct answer is "charge."Rate this question:
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- 25.
When a beta particle is ejected from a nucleus, the nucleus then has slightly
- A.
Greater mass and charge.
- B.
Greater mass and smaller charge.
- C.
Smaller mass and significantly greater charge.
- D.
Smaller charge and significantly greater mass.
Correct Answer
C. Smaller mass and significantly greater charge.Explanation
When a beta particle is ejected from a nucleus, it carries away a negative charge and a very small mass. This results in the nucleus having a smaller mass because it has lost a particle, and a significantly greater charge because it has lost a negatively charged particle.Rate this question:
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- 26.
When a gamma ray is emitted by a nucleus, the nucleus then has appreciably less
- A.
Mass.
- B.
Charge.
- C.
Both of these
- D.
Neither of these
Correct Answer
D. Neither of theseExplanation
When a gamma ray is emitted by a nucleus, it does not result in a change in the mass or charge of the nucleus. Gamma rays are high-energy photons that are released during nuclear decay or other nuclear processes. They do not carry any charge and have no mass. Therefore, the emission of a gamma ray does not affect the mass or charge of the nucleus from which it is emitted.Rate this question:
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- 27.
When a gamma ray is emitted by a nucleus, the nucleus then has less
- A.
Energy.
- B.
Charge.
- C.
Both of these
- D.
Neither of these
Correct Answer
A. Energy.Explanation
When a gamma ray is emitted by a nucleus, it carries away energy from the nucleus. This means that the nucleus loses energy in the process. The emission of a gamma ray does not affect the charge of the nucleus, so it does not lose or gain any charge. Therefore, the correct answer is "energy."Rate this question:
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- 28.
The fate of the world's uranium supply is to eventually become
- A.
Alpha and beta particles.
- B.
Iron.
- C.
Lead.
Correct Answer
C. Lead.Explanation
Uranium undergoes a process called radioactive decay, where it breaks down into smaller particles over time. This decay chain eventually leads to the formation of lead. Therefore, the fate of the world's uranium supply is to eventually become lead.Rate this question:
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- 29.
The origin of cosmic rays is the
- A.
Earth.
- B.
Clouds.
- C.
Sun.
- D.
Cosmos.
- E.
None of these
Correct Answer
D. Cosmos.Explanation
Cosmic rays are high-energy particles that originate from outside the Earth's atmosphere. They are believed to come from various astrophysical sources, such as supernovae, black holes, and active galactic nuclei. These sources are located in the cosmos, which refers to the entire universe beyond our planet. Therefore, the correct answer is "cosmos" as it accurately represents the origin of cosmic rays.Rate this question:
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- 30.
The high temperature of the Earth's interior is due mostly to
- A.
Great internal pressure.
- B.
Friction, as plates move past one another.
- C.
The Earth's natural heat.
- D.
Radioactivity.
Correct Answer
D. Radioactivity.Explanation
The high temperature of the Earth's interior is primarily due to radioactivity. Radioactive elements such as uranium, thorium, and potassium decay over time, releasing heat in the process. This heat is trapped within the Earth's core and mantle, leading to high temperatures. While great internal pressure and friction from plate movements also contribute to the Earth's heat, radioactivity is the main factor responsible for the high temperatures in the Earth's interior.Rate this question:
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- 31.
Pure elements can be transformed into entirely different elements. This statement at the present time is
- A.
True.
- B.
False.
Correct Answer
A. True.Explanation
This statement is true because pure elements can indeed be transformed into entirely different elements through various chemical processes such as nuclear reactions or combination with other elements. These transformations can result in the creation of new elements with different atomic numbers and properties.Rate this question:
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- 32.
Which of the following isotopes is radioactive?
- A.
Carbon-12
- B.
Carbon-14
- C.
Both are radioactive.
- D.
Neither is radioactive in nature.
Correct Answer
B. Carbon-14Explanation
Carbon-14 is the radioactive isotope. Radioactive isotopes are unstable and undergo radioactive decay, which means they emit radiation in the form of particles or electromagnetic waves. Carbon-14 is used in radiocarbon dating to determine the age of ancient artifacts and fossils. On the other hand, Carbon-12 is stable and does not undergo radioactive decay.Rate this question:
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- 33.
There is a greater proportion of carbon 14 in
- A.
New bones.
- B.
Old bones.
- C.
Same in each
Correct Answer
A. New bones.Explanation
New bones have a greater proportion of carbon 14 compared to old bones because carbon 14 is a radioactive isotope that decays over time. Since new bones have recently formed, they have not had enough time for a significant amount of carbon 14 to decay, resulting in a higher proportion of carbon 14. On the other hand, old bones have been around for a longer period of time, allowing more carbon 14 to decay, resulting in a lower proportion of carbon 14. Therefore, the correct answer is new bones.Rate this question:
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- 34.
Carbon 14 is produced in the atmosphere principally by
- A.
Plants and animals.
- B.
Cosmic-ray bombardment.
- C.
Nitrogen bombardment.
- D.
Photosynthesis.
- E.
None of these
Correct Answer
B. Cosmic-ray bombardment.Explanation
Carbon 14 is produced in the atmosphere principally by cosmic-ray bombardment. Cosmic rays, which are high-energy particles from outer space, collide with atoms in the atmosphere and cause nuclear reactions. One of these reactions involves the collision of cosmic rays with nitrogen atoms, resulting in the production of carbon 14. This radioactive isotope of carbon is then incorporated into the carbon dioxide molecules in the atmosphere, which are taken up by plants during photosynthesis and subsequently passed on to animals through the food chain. Therefore, while plants and animals are involved in the carbon cycle, the primary source of carbon 14 is cosmic-ray bombardment.Rate this question:
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- 35.
Carbon dating requires that the object being tested contain
- A.
Organic material.
- B.
Inorganic material.
- C.
Charcoal.
- D.
Sugar molecules.
- E.
None of these
Correct Answer
A. Organic material.Explanation
Carbon dating is a method used to determine the age of organic materials based on the decay of the radioactive isotope carbon-14. This isotope is only present in organic materials, such as plants and animals, that have obtained carbon from the atmosphere through photosynthesis or consumption. Inorganic materials, like rocks or minerals, do not contain carbon-14 and therefore cannot be accurately dated using this method. Charcoal and sugar molecules are examples of organic materials that can be tested using carbon dating. Therefore, the correct answer is organic material.Rate this question:
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- 36.
All deposits of natural uranium contain appreciable amounts of
- A.
Iron.
- B.
Lead.
- C.
Gold.
- D.
All of these
- E.
None of these particularly
Correct Answer
B. Lead.Explanation
All deposits of natural uranium contain appreciable amounts of lead. This is because lead is a common element found in the Earth's crust and is often associated with uranium deposits. As uranium undergoes radioactive decay over time, it eventually transforms into lead through a series of intermediate elements. Therefore, it is expected to find lead in all natural uranium deposits. Iron and gold, on the other hand, are not typically found in significant amounts in uranium deposits.Rate this question:
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- 37.
Most of the radioactivity we personally encounter comes from
- A.
Fallout from past and present testing of nuclear weapons.
- B.
Nuclear power plants.
- C.
Medical X rays.
- D.
The natural environment.
Correct Answer
D. The natural environment.Explanation
The correct answer is the natural environment. This is because radioactivity is naturally present in the environment due to the presence of radioactive elements in the Earth's crust, such as uranium and thorium. These elements decay over time and release radiation. Additionally, cosmic radiation from the sun and outer space also contributes to the radioactivity in the natural environment. While fallout from nuclear weapons testing, nuclear power plants, and medical X-rays do contribute to radioactivity exposure, the majority of the radioactivity we encounter on a daily basis comes from the natural environment.Rate this question:
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- 38.
The amount of radiation we personally encounter that originates in the Earth's and the atmosphere's natural background is
- A.
A trace amount.
- B.
About a quarter.
- C.
About half.
- D.
More than half.
Correct Answer
D. More than half.Explanation
The correct answer is more than half. This means that the amount of radiation we personally encounter from the Earth's and the atmosphere's natural background is greater than 50%. This could be due to various sources of natural radiation such as cosmic rays, radon gas, and radioactive elements present in the Earth's crust. These sources contribute to the overall radiation exposure that individuals experience on a daily basis.Rate this question:
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- 39.
The source of the Earth's natural heat is
- A.
Molten-hot lava.
- B.
Pressure on the Earth's interior.
- C.
Radioactive decay in the Earth's core.
- D.
Solar energy in the form of fossil fuels.
Correct Answer
C. Radioactive decay in the Earth's core.Explanation
The correct answer is radioactive decay in the Earth's core. Radioactive decay refers to the process in which unstable atomic nuclei release energy in the form of radiation. This process occurs in the Earth's core, where there are large amounts of radioactive elements such as uranium and thorium. The heat generated from this radioactive decay is a significant source of the Earth's natural heat.Rate this question:
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- 40.
The most harmful radiations are those that
- A.
Kill living cells.
- B.
Damage living cells.
Correct Answer
B. Damage living cells.Explanation
The most harmful radiations are those that damage living cells. This is because radiation can cause mutations in DNA, disrupt cellular processes, and lead to cell death. These harmful effects can have serious consequences for living organisms, including increased risk of cancer and other diseases.Rate this question:
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- 41.
Radioactivity in the world is something
- A.
Relatively new.
- B.
As old as the world itself.
Correct Answer
B. As old as the world itself.Explanation
The correct answer is "as old as the world itself." This answer suggests that radioactivity has existed since the beginning of time and is not a recent phenomenon. It implies that radioactivity is a natural occurrence that has been present throughout the history of the world.Rate this question:
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- 42.
The helium in a child's balloon is composed of
- A.
Alpha-particle remnants of previous radioactive processes.
- B.
Former beta particles.
- C.
Both of these
- D.
None of these
Correct Answer
C. Both of theseExplanation
The correct answer is both of these. Helium in a child's balloon can be composed of alpha-particle remnants of previous radioactive processes, as well as former beta particles. Alpha particles are made up of two protons and two neutrons, and they can be produced during radioactive decay. Beta particles, on the other hand, can be electrons or positrons emitted during certain types of radioactive decay. Therefore, the helium in a child's balloon can contain remnants of both alpha and beta particles.Rate this question:
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- 43.
A sample of relatively active radioactive material is somewhat
- A.
Warmer than the environment.
- B.
Cooler than the environment.
- C.
Neither really
Correct Answer
A. Warmer than the environment.Explanation
Radioactive materials release energy in the form of radiation, which can cause the material to become warmer than its surrounding environment. This is due to the radioactive decay process, where unstable atomic nuclei release energy as they transform into more stable forms. As a result, the sample of radioactive material will have a slightly higher temperature compared to its surroundings.Rate this question:
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- 44.
Which body is heated in its interior by nuclear processes?
- A.
The sun
- B.
The Earth
- C.
Both
- D.
Neither
Correct Answer
C. BothExplanation
Both the sun and the Earth are heated in their interiors by nuclear processes. The sun's core undergoes nuclear fusion, where hydrogen atoms combine to form helium and release a tremendous amount of energy in the process. This energy is what powers the sun and gives off heat and light. On the other hand, the Earth's interior is heated by radioactive decay. Radioactive elements present in the Earth's core release heat as they decay over time. This heat is responsible for driving geological processes such as plate tectonics and volcanic activity.Rate this question:
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- 45.
When radium (A = 88) emits an alpha particle, the resulting nucleus has atomic number
- A.
86.
- B.
88.
- C.
90.
- D.
92.
- E.
None of these
Correct Answer
A. 86.Explanation
When radium (atomic number 88) emits an alpha particle, it loses two protons, resulting in a new nucleus with an atomic number of 86. This is because an alpha particle consists of two protons and two neutrons, so when it is emitted, the atomic number decreases by two. Therefore, the correct answer is 86.Rate this question:
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- 46.
When thorium (A = 90) emits a beta particle, the resulting nucleus has atomic number
- A.
88.
- B.
89.
- C.
90.
- D.
92.
- E.
None of these
Correct Answer
E. None of theseExplanation
When thorium (A = 90) emits a beta particle, it undergoes beta decay, where a neutron is converted into a proton and a beta particle (electron) is emitted. This means that the atomic number of the resulting nucleus increases by 1. Therefore, the resulting nucleus after thorium emits a beta particle would have an atomic number of 91, not any of the given options.Rate this question:
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- 47.
When a nucleus emits a positron, its atomic number
- A.
Increases by 1.
- B.
Decreases by 1.
- C.
Doesn't change.
Correct Answer
B. Decreases by 1.Explanation
When a nucleus emits a positron, it undergoes a process called beta plus decay. In this process, a proton in the nucleus is converted into a neutron, and a positron is emitted. Since a proton has a positive charge and a neutron has no charge, the emission of a positron results in a decrease in the atomic number of the nucleus by 1. Therefore, the correct answer is that the atomic number decreases by 1.Rate this question:
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- 48.
When a nucleus emits a beta particle, its atomic number
- A.
Increases by 1.
- B.
Decreases by 1.
- C.
Increases by 2.
- D.
Decreases by 2.
- E.
None of these
Correct Answer
A. Increases by 1.Explanation
When a nucleus emits a beta particle, it undergoes beta decay, which involves the conversion of a neutron into a proton. Since the atomic number represents the number of protons in the nucleus, when a neutron is converted into a proton, the atomic number increases by 1. Therefore, the correct answer is that the atomic number increases by 1.Rate this question:
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- 49.
An element will decay to an element with higher atomic number in the periodic table if it emits
- A.
A beta particle.
- B.
A gamma ray.
- C.
A proton.
- D.
An alpha particle.
- E.
None of these
Correct Answer
A. A beta particle.Explanation
When an element emits a beta particle, it means that one of its neutrons is converted into a proton and an electron. This results in the atomic number of the element increasing by one, as a proton is added to the nucleus. Therefore, the element decays to an element with a higher atomic number in the periodic table. Gamma rays, protons, and alpha particles do not cause an increase in atomic number, so they are not responsible for this type of decay.Rate this question:
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- 50.
When the hydrogen isotope tritium-3 emits a beta particle, it becomes an isotope of
- A.
Hydrogen.
- B.
Helium.
- C.
Lithium.
- D.
Carbon.
- E.
None of these
Correct Answer
B. Helium.Explanation
When the hydrogen isotope tritium-3 emits a beta particle, it loses one neutron and gains one proton, resulting in the formation of an isotope of helium. This is because a beta particle is essentially an electron, and when it is emitted, it causes a neutron to convert into a proton. Therefore, the resulting isotope is helium, which has two protons and two neutrons.Rate this question:
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Mar 21, 2023Quiz Edited by
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Mar 13, 2013Quiz Created by
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