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Conceptual Physics 1 Test 7 (Chapters 19 and 20)

Study chapters 19 and 20 for conceptual physics 1
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The tendency of some elements, such as uranium, to emit radiation as a result of changes in the atomic nucleus.
radioactivity
A helium atom nucleus, which consists of two neutrons and two protons and is ejected by certain radioactive elements.
alpha particle
An electron ejected from an atomic nucleus during the radioactive decay of certain nuclei.
beta particle
High-energy radiation emitted by the nuclei of radioactive atoms.
gamma radiation
The force of interaction between all nucleons, effective only at very, very, very close distances.
strong nuclear force
The conversion of an atomic nucleus of one element to an atomic nucleus of another element through a loss or gain of protons
transformation
The time required for half the atoms in a sample of a radioactive isotope to decay.
half-life
The process of estimating the age of once living material by measuring the amount of radioactive isotope of carbon present in the material.
carbon-14 dating
a self-sustaining reaction in which the products of one fusion event stimulate further events
chain reaction
the splitting of a heavy nucleus into two lighter nuclei, accomponied by the release of much energy.
nuclear fission
The joining together of light nuclei to form a heavier
nuclear fusion
nuclear fusion produced by high temps.
thermonuclear fusion
How do the electric charges of alpha, beta, and gamma rays differ from one another?
alpha is positively charged, beta is negatively charge, and gamma has electromagnetic radiation
Which of the three rays has the greatest penetrating power
gamma
What is the origin of most radiation you encounter?
In the Earth and in space
Is radioactivity on Earth something relatively new?
no
How are the strong nuclear force and the electric force different from each other?
Nuclear force diminishes with distance but electrical force does not.
What role do neutrons play in the atomic nucleus?
Neutrons act like "nuclear cement" attracting neutrons and protons.
When thorium, atomic number 90, decays by emitting an alpha particle, what is the atomic number of the resulting nucleus?
88
When thorium decays by emitting a beta particle, what is the atomic number of the resulting nucleus?
91
What changes in atomic number occurs when a nucleus emits an alpha particle? A beta particle?
An alpha particle loses 2 protons which lowers it by 2. A beta particle changing a neutron to a proton making the atomic number go up by 1.
What is a long range fate of all the uranium that exists in the world today?
Uranium decays to lead.
What is meant by radioactive half-life?
The time needed for half the radioactive atoms to decay.
What is the half-life of radium-226
1620 years
How does the decay rate of an isotope relate its half-life?
The half-life is the time it takes for half the radioactive atoms to decay.
What do atomic rays have to do with transmutation?
They cause atoms in the atmosphere to transmute.
How is carbon-14 produced in the atmosphere?
Nitrogen that captures a neutron.
Which is radioactive, carbon-12 or carbon-14?
Carbon-14
Why is there more carbon-14 in living bones than in once-living ancient bones of the same mass?
The carbon-14 is decaying.
Why is carbon-14 dating useless for dating old coins but not old pieces of cloth?
Cloth is made of plants, plants have carbon-14, metals do not
Why is lead found in all deposits of uranium ores?
Uranium decays into lead.
What does the proportion of lead and uranium in rock tell us about the age of the rock?
The more lead and less uranium, the older it is.