Physics Chapter 33

Once an alpha particle is outside the nucleus it is A) electrostatically repelled. B) free to wander about the nucleus. C) quickly bound to a neighboring nucleus. D) radioactive.

A) electrostatically repelled.

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

A) nitrogen-14.

The half-life on an isotope is one day. At the end of three days, how much of the isotope remains? A) one-eighth B) none of these C) none D) one-quarter E) one-half

A) one-eighth

What daughter isotopes are produced when a neutron combines with a nucleus of 235/29 U? Assume that three neutrons are also produced in the reaction. A) 140/56 Ba, 95/36 Kr B) 142/56 Ba, 93/36 Kr C) 141/56 Ba, 94/36 Kr D) 140/56 Ba, 93/36 Kr

A) 140/56 Ba, 95/36 Kr

The half life of carbon 14 is 5730 years. If a 1-gram sample of old carbon is 1/8 as radioactive as 1-gram of a current sample, then the age of the old sample is about A) 17,200 years. B) 22,900 years. C) 716 years. D) 11,500 years. E) 46,000 years.

A) 17,200 years.

During b+ decay A) a proton is transformed to a neutron. B) a neutron is transformed to a proton. C) a proton is ejected from the nucleus. D) a neutron is ejected from the nucleus.

A) a proton is transformed to a neutron.

In beta decay A) an electron is emitted. B) an electron decays into another particle. C) a neutron is emitted. D) a proton is emitted.

A) an electron is emitted.

A β- particle is also known as A) an electron. B) a photon. C) a helium nucleus. D) a positron.

A) an electron.

When an atom undergoes nuclear transmutation, the result is a completely different A) atom of a different element B) atom of the same element C) isotope of the same element. D) ion of the same element.

A) atom of a different element

Most of the radioactivity we personally encounter comes from A) the natural environment. B) nuclear power plants. C) fallout from past and present testing of nuclear weapons. D) medical X rays.

A) the natural environment.

Which of the following is most nearly the same as a gamma ray? A) visible light B) a neutron C) a proton D) an alpha particle E) a beta ray

A) visible light

When radium (A = 88) emits an alpha particle, the resulting nucleus has atomic number A) 88. B) 86. C) 92. D) 90. E) none of these

B) 86.

What happens to the half-life of a radioactive substance as it decays? A) It could do any of these. B) It remains constant. C) It decreases. D) It increases.

B) It remains constant.

Which of the following statements concerning the nuclear force is false? A) The nuclear force is very short-ranged. B) The nuclear force is very weak and much smaller in relative magnitude than the electrostatic and gravitational forces. C) The nuclear force is attractive and not repulsive. D) The nuclear force acts on both protons and neutrons.

B) The nuclear force is very weak and much smaller in relative magnitude than the electrostatic and gravitational forces.

An element will decay to an element with higher atomic number in the periodic table if it emits A) none of these B) a beta particle. C) an alpha particle. D) a proton. E) a gamma ray.

B) a beta particle.

A gamma ray is also known as A) a positron. B) a photon. C) an electron. D) a helium nucleus.

B) a photon.

Alpha rays can penetrate, at most A) several centimeters of lead. B) a piece of paper. C) several millimeters of aluminum. D) air only.

B) a piece of paper.

A b+ particle is also known as A) a helium nucleus. B) a positron. C) an electron. D) a photon.

B) a positron.

Energy released by the sun results from the process wherein atomic nuclei A) break apart. B) combine. C) both of these D) none of these

B) combine.

When a b+ particle is emitted from an unstable nucleus, the atomic number of the nucleus A) none of the given answers B) decreases by 1. C) increases by 1. D) does not change.

B) decreases by 1.

When an alpha particle is emitted from an unstable nucleus, the atomic mass number of the nucleus A) increases by 4. B) decreases by 4. C) increases by 2. D) decreases by 2.

B) decreases by 4.

When a b- particle is emitted from an unstable nucleus, the atomic mass number of the nucleus A) decreases by 1. B) does not change. C) increases by 1. D) none of the given answers

B) does not change.

When the hydrogen isotope tritium-3 emits a beta particle, it becomes an isotope of A) carbon. B) helium. C) hydrogen. D) lithium. E) none of these

B) helium.

When a b- particle is emitted from an unstable nucleus, the atomic number of the nucleus A) does not change. B) increases by 1. C) none of the given answers D) decreases by 1.

B) increases by 1.

Generally speaking, the larger a nucleus is, the greater its A) none of these B) instability. C) stability. D) permeability

B) instability.

An alpha particle will be attracted to a A) positive charge. B) negative charge. C) proton. D) gamma ray.

B) negative charge.

A gram of radioactive material has a half-life of one year. After 4 years, how much radioactive material will be left? A) 0 g B) none of these C) 1/4 g D) 1/2 g E) 1/8 g

B) none of these

When a gamma ray is emitted from an unstable nucleus, A) the number of neutrons drops by one and the number of protons increases by one. B) there is no change in either the number of neutrons or the number of protons. C) the number of neutrons and the number of protons drop by two. D) none of the given answers

B) there is no change in either the number of neutrons or the number of protons.

An α particle is also known as A) a positron. B) a photon. C) a helium nucleus. D) an electron.

C) a helium nucleus.

During b- decay A) a neutron is ejected from the nucleus. B) a proton is transformed to a neutron. C) a neutron is transformed to a proton. D) a proton is ejected from the nucleus.

C) a neutron is transformed to a proton.

Which particle has the most mass? A) beta B) gamma C) alpha D) electron

C) alpha

As the number of protons in the nucleus increases, the repulsive force A) drops to zero. B) remains unchanged. C) becomes stronger. D) becomes weaker.

C) becomes stronger.

When an alpha particle is ejected from a nucleus, the nucleus then has less A) mass. B) neither of these C) both of these D) charge.

C) both of these

When a nucleus emits a beta particle, its atomic number A) none of these B) remains constant, but its mass number changes. C) changes, but its mass number remains constant. D) changes, and so does its mass number. E) remains constant, and so does its mass number.

C) changes, but its mass number remains constant.

When an alpha particle is emitted from an unstable nucleus, the atomic number of the nucleus A) increases by 2. B) increases by 4. C) decreases by 2. D) decreases by 4.

C) decreases by 2.

When a gamma ray is emitted by a nucleus, the nucleus then has less A) charge. B) neither of these C) energy. D) both of these

C) energy.

When a nucleus emits a beta particle, its atomic number A) increases by 2. B) decreases by 2. C) increases by 1. D) decreases by 1. E) none of these

C) increases by 1.

Compared to the electrostatic force, the nuclear force between adjacent protons in a nucleus is A) about the same size. B) much weaker. C) much larger. D) only slightly larger.

C) much larger.

When a gamma ray is emitted by a nucleus, the nucleus then has appreciably less A) charge. B) mass. C) neither of these D) both of these

C) neither of these

When thorium (A = 90) emits a beta particle, the resulting nucleus has atomic number A) 88. B) 92. C) none of these D) 89. E) 90.

C) none of these

In all three types of radioactive decay, what value is conserved in addition to electric charge, energy, and momentum? A) neutron number B) atomic number C) nucleon number D) none of the given answers

C) nucleon number

The half-life of an isotope is one day. At the end of two days the amount that remains is A) one-eighth. B) none of these C) one-quarter. D) one-half. E) none.

C) one-quarter.

Carbon dating requires that the object being tested contain A) sugar molecules. B) inorganic material. C) organic material. D) none of these E) charcoal.

C) organic material.

Electric forces within an atomic nucleus tend to A) spin the electrons B) hold it together. C) push it apart. D) none of these

C) push it apart.

Gamma rays can penetrate, at most A) air only. B) a piece of paper. C) several centimeters of lead. D) several millimeters of aluminum.

C) several centimeters of lead.

Beta rays can penetrate, at most A) several centimeters of lead. B) air only. C) several millimeters of aluminum. D) a piece of paper.

C) several millimeters of aluminum.

A certain radioactive isotope placed near a Geiger counter registers 160 counts per second. Eight hours later, the counter registers 10 counts per second. What is the half life of the isotope? A) 8 hours B) 4 hours C) 6 hours D) 2 hours E) none of these

D) 2 hours

Alpha particles have an atomic mass equal to A) 1. B) 6. C) 2. D) 4.

D) 4.

In the radioactive formula, 220/86 Rn => 216/84 Po + X, what does X represent? A) 0/1 e B) 0/.1 e C) Lambda D) 4/2 He

D) 4/2 He

Control is exercised in a nuclear reactor by A) emitting fast neutrons with a moderator. B) both of these C) none of these D) absorbing excess neutrons with control rods.

D) absorbing excess neutrons with control rods.

The half-life of a radioactive substance is INDEPENDENT of A) the number (if large enough) of atoms in the substance. B) the temperature of the substance. C) the age of the substance. D) all of these E) whether the substance exists in an elementary state or in a compound.

D) all of these

The existence of the neutrino was postulated in order to explain A) gamma emission. B) alpha decay. C) fission. D) beta decay.

D) beta decay.

When a beta particle is ejected from a nucleus, the nucleus then has a greater A) neither of these B) mass. C) both of these D) charge.

D) charge.

Of the main types of radiation emitted from naturally radioactive isotopes, which is the most penetrating? A) beta B) positron C) alpha D) gamma

D) gamma

Which process generates energy in the Sun? A) transmutation B) nuclear fission C) chain reaction D) nuclear fusion

D) nuclear fusion

When a beta particle is ejected from a nucleus, the nucleus then has slightly A) greater mass and smaller charge. B) greater mass and charge. C) smaller charge and significantly greater mass. D) smaller mass and significantly greater charge.

D) smaller mass and significantly greater charge.

There is a limit to the size of a stable nucleus because of A) the weakness of the electrostatic force. B) none of the given answers C) the weakness of the gravitational force. D) the limited range of the strong nuclear force.

D) the limited range of the strong nuclear force.

Which radiation has no electric charge associated with it? A) all of these B) none of these C) alpha rays D) beta rays E) gamma rays

E) gamma rays

An element emits 1 alpha particle, 1 positron, and 3 beta particles. Its atomic number A) increases by 2. B) increases by 1. C) decreases by 1. D) decreases by 2. E) stays the same.

E) stays the same.