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9th Grade Physics > Radioactivity and Nuclear Power > Flashcards

Radioactivity and Nuclear Power Flashcards

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1
Q

What are nucleons?

A

Protons and neutrons, the particles in the nucleus.

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2
Q

What holds the nucleus together?

A

The strong nuclear force.

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3
Q

For heavier elements, do protons outnumber neutrons or the other way around in the nucleus?

A

Neutrons outnumber protons.

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4
Q

Why do some undergo radioactive decay?

A

To achieve greater stability.

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5
Q

What are the three types of radioactive decay we studied?

A

Alpha, beta and gamma decay.

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6
Q

Which of the three types of radioactive decay are unaffected by a magnetic field, alpha, beta or gamma?

A

Gamma.

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7
Q

Which of the three types of radioactive decay has the most mass, alpha, beta or gamma?

A

Alpha.

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8
Q

A beta particle is also known as a(n) __________

A

Electron

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9
Q

Which of the three types of radioactive decay has the greatest penetrating power, alpha, beta or gamma?

A

Gamma

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10
Q

Isotopes of an element are chemically identical but differ in the number of __________

A

Neutrons

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11
Q

A hydrogen atom with one neutron is called ________

A

Deuterium

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12
Q

The time needed for half of the radioactive atoms in a sample to decay is called a ___________

A

Half-life

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13
Q

True or False. Rates of radioactive decay appear to be absolutely constant, unaffected by any external conditions.

A

True.

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14
Q

If a 24-gram sample of a radioactive substance with a half-life of 7 days decays over 3 weeks, how much is left?

A

3 grams.

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15
Q

Which of the three radioactive decay modes - alpha, beta or gamma - creates an isotope of a different element?

A

Alpha and beta

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16
Q

Which of the three radioactive decay modes - alpha, beta or gamma - creates an isotope of an element with a higher atomic number?

A

Beta

17
Q

Scientists can figure out how long ago a plant or animal died by measuring _________ of carbon-14 to carbon-12 in the remains.

A

The ratio.

18
Q

True or false. Carbon dating can be used to determine how long ago a dinosaur lived.

A

False. Carbon dating can only be used for samples 50,000 years old at the most. Dinosaurs died out 65 million years ago.

19
Q

Each year, we are exposed to natural radiation from ______

A

Cosmic rays, minerals from the Earth and radon gas.

20
Q

The ago of the Dead Sea Scrolls was found by carbon dating. Could this technique work if they were instead stone tablets?

A

No because carbon dating only works on things that were once alive.

21
Q

The splitting of atomic nuclei is called nuclear _______

A

Fission.

22
Q

A situation where one reaction event stimulates one or more additional reaction events to keep the process going is called a _______________

A

Chain reaction

23
Q

Which uranium isotope undergoes fission - U-235 or U-238?

A

U-235

24
Q

True or False. Uranium ore contains much more U-235 than U-238.

A

False. Uranium ore contains only about 0.7% U-235.

25
Q

What do you call the amount of mass for which each fission event produces, on the average, one additional fission event?

A

Critical mass.

26
Q

Uranium samples must be ______ in order to sustain a chain reaction.

A

Enriched (increase the percentage of U-235)

27
Q

In order to keep the nuclear reactor from overheating, the chain reaction is regulated with _____________.

A

Control rods

28
Q

Control rods regulate the chain reaction by __________

A

Absorbing neutrons.

29
Q

Breeder reactors convert non-fissionable uranium isotope into fissionable ___________ isotope.

A

Plutonium

30
Q

When light nuclei are combined, the process is called _________

A

Nuclear fusion

31
Q

True or False. Gram for gram, fission produces more energy than fusion.

A

False.

32
Q

What is the biggest obstacle to controlling nuclear fusion?

A

Extremely high temperatures are needed

33
Q

What would be the benefits to nuclear fusion as a power source?

A

No radioactive waste, more energy per gram, cheap and virtually unlimited fuel.

34
Q

Why are there no appreciable deposits of plutonium in Earth’s crust?

A

The vast majority of plutonium atoms have radioactively decayed into isotopes of other elements.

9th Grade Physics (10 decks)

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