Chapter 33

The Atomic Nucleus and Radioactivity

An X-ray is part of a family of

a. subnuclear particles.

b. electromagnetic waves.

c. atoms.

d. isotopes.

An X-ray is part of a family of

a. subnuclear particles.

b. electromagnetic waves.

c. atoms.

d. isotopes.

A sample of radioactive material 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 energetic particles.

A sample of radioactive material 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 energetic particles.

Which of these rays cannot be deflected by electric or magnetic

means?

a. Alpha

b. Beta

c. Gamma

d. All can be deflected by passing beams through a magnetic or electric field.

Which of these rays cannot be deflected by electric or magnetic

means?

a. Alpha

b. Beta

c. Gamma

d. All can be deflected by passing beams through a magnetic or electric field.

Which of these is the most penetrating in common materials?

a. Alpha

b. Beta

c. Gamma

d. All are equally penetrating.

Which of these is the most penetrating in common materials?

a. Alpha

b. Beta

c. Gamma

d. All are equally penetrating.

The benefits of properly using radioactivity include

a. measuring the proper amount of fertilizer on farms.

b. tracing medicines in the body.

c. irradiating food to kill harmful microorganisms.

d. All of these.

The benefits of properly using radioactivity include

a. measuring the proper amount of fertilizer on farms.

b. tracing medicines in the body.

c. irradiating food to kill harmful microorganisms.

d. All of these.

Most of the radiation in Earth’s biosphere

a. is the result of military activities.

b. originates from nuclear power plants.

c. occurs as natural background radiation.

d. is due to human negligence.

Most of the radiation in Earth’s biosphere

a. is the result of military activities.

b. originates from nuclear power plants.

c. occurs as natural background radiation.

d. is due to human negligence.

Which type of radiation from cosmic sources predominates in

the lower atmosphere?

a. Alpha

b. Beta

c. Gamma

d. None predominates because all three are about equally abundant.

Which type of radiation from cosmic sources predominates in

the lower atmosphere?

a. Alpha

b. Beta

c. Gamma

d. None predominates because all three are about equally abundant.

Explanation: Gamma is the most penetrating, in the atmosphere and otherwise.

In the nucleus of an atom, the strong force is a relatively

a. short-range force.

b. long-range force.

c. unstable force.

d. neutralizing force.

In the nucleus of an atom, the strong force is a relatively

a. short-range force.

b. long-range force.

c. unstable force.

d. neutralizing force.

Uranium-235, uranium-238, and uranium-239 are different

a. elements.

b. ions.

c. isotopes.

d. nucleons.

Uranium-235, uranium-238, and uranium-239 are different

a. elements.

b. ions.

c. isotopes.

d. nucleons.

Which of these is NOT a nucleon?

a. Proton

b. Neutron

c. Electron

d. All are nucleons.

Which of these is NOT a nucleon?

a. Proton

b. Neutron

c. Electron

d. All are nucleons.

The half-life of carbon-14 is about 5730 years, which means that the present amount in your bones will reduce to zero

a. when you die.

b. in about 5730 years.

c. in about twice 5730 years.

d. None of these.

The half-life of carbon-14 is about 5730 years, which means that the present amount in your bones will reduce to zero

a. when you die.

b. in about 5730 years.

c. in about twice 5730 years.

d. None of these.

Explanation: In theory, the amount never reaches zero. In eons to come, trace amounts of the carbon-14 in your bones, even if completely dissolved, will still exist.

A certain radioactive element has a half-life of 1 hour. If you start with a 1.000-gram

sample of the element at noon, how much of this same element will be left at 4:00 PM?

a. 0.5 grams

b. 0.25 grams

c. 0.125 grams

d. 0.063 grams

A certain radioactive element has a half-life of 1 hour. If you start with a 1.000-gram

sample of the element at noon, how much of this same element will be left at 4:00 PM?

a. 0.5 grams

b. 0.25 grams

c. 0.125 grams

d. 0.063 grams

Explanation: Cut 1 in half 4 times and get 1/16, or 0.0625, or roughly 0.063.

A friend produces a Geiger counter to check your surroundings. It ticks. Another friend who

normally has the most fear of what is least understood, 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. Not to worry, for what is being detected is natural background radiation.

d. Wear heavy clothes.

A friend produces a Geiger counter to check your surroundings. It ticks. Another friend who

normally has the most fear of what is least understood, 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. Not to worry, for what is being detected is natural background radiation.

d. Wear heavy clothes.

Atoms can transmute into completely different atoms in

a. nature.

b. laboratories.

c. Both of these.

d. None of these.

Atoms can transmute into completely different atoms in

a. nature.

b. laboratories.

c. Both of these.

d. None of these.

Explanation: Atomic transmutation occurs in nature, in laboratories, and as far as we know, throughout the cosmos.

When a particular isotope emits an alpha particle, what new element

results?

a. The same element, but with decreased mass

b. One with both atomic number and atomic mass decreased by 2

c. One with atomic number decreased by 2 and atomic mass decreased by 4

d. One with atomic number increased by 2 and atomic mass increased by 4

When a particular isotope emits an alpha particle, what new element

results?

a. The same element, but with decreased mass

b. One with both atomic number and atomic mass decreased by 2

c. One with atomic number decreased by 2 and atomic mass decreased by 4

d. One with atomic number increased by 2 and atomic mass increased by 4

When a particular isotope emits a beta particle, what new element results?

a. The same element with the same mass

b. One with both atomic number and atomic mass reduced by 1

c. One with atomic number increased by 1 and atomic mass reduced by 1

d. One with atomic mass increased by 1 and no change in atomic mass

When a particular isotope emits a beta particle, what new element results?

a. The same element with the same mass

b. One with both atomic number and atomic mass reduced by 1

c. One with atomic number increased by 1 and atomic mass reduced by 1

d. One with atomic mass increased by 1 and no change in atomic mass

Explanation: Beta emission increases the nuclear charge of the isotope by 1, but has negligible effect on mass.

A certain element emits one alpha particle, and its products then emit two

beta particles in succession. The atomic number of the resulting element is

changed by

a. 0.

b. minus 1.

c. minus 2.

d. None of these.

A certain element emits one alpha particle, and its products then emit two

beta particles in succession. The atomic number of the resulting element is

changed by

a. 0.

b. minus 1.

c. minus 2.

d. None of these.

Explanation: Removal of the alpha decreases atomic number by 2, but removal of two electrons increases it by 2, so there is no net change in atomic number.

Carbon-14 is a radioactive isotope of carbon that is primarily produced by

cosmic radiation in the

a. atmosphere.

b. food we eat.

c. Earth’s interior.

d. fallout of nuclear bomb tests.

Carbon-14 is a radioactive isotope of carbon that is primarily produced by

cosmic radiation in the

a. atmosphere.

b. food we eat.

c. Earth’s interior.

d. fallout of nuclear bomb tests.

Comment: C-14 may exist in food, Earth’s interior, and even in bomb fallout, but it is produced by cosmic rays in the atmosphere.

To determine the age of the oldest geological materials, scientists turn to

the radioactivity of

a. carbon.

b. uranium.

c. lead.

d. All of these.

To determine the age of the oldest geological materials, scientists turn to

the radioactivity of

a. carbon.

b. uranium.

c. lead.

d. All of these.

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 the coal-fired plant

a. needs shielding.

b. needs better news coverage in the media.

c. has been contaminated.

d. should be converted to a “nuke.”

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 the coal-fired plant

a. needs shielding.

b. needs better news coverage in the media.

c. has been contaminated.

d. should be converted to a “nuke.”