Radioactivity

Question 1

March 1, 1896: Discovers Radioactivity (American Physical Society, 2008)

Answer 1

Henri Becquerel

Question 2

is the ability of a crystal to absorb light and reemit light sometime after the exciting light has been removed.

Answer 2

Phosphorescence

Question 3

Becquerel reported at the French Academy of Science meeting on ________ that the phosphorescent uranium salts absorbed sunlight and emitted a penetrating radiation similar to x-rays.

Answer 3

February 24, 1896

Question 4

In 1898, They figured out how to measure the intensity of the radioactivity, and soon found other radioactive elements: polonium, thorium and radium.

Answer 4

Marie and Pierre Curie

Question 5

Concepts of radioactivity that the atoms of the substance spontaneously emit invisible but energetic radiations, which can penetrate materials that are opaque to visible light

Answer 5

(Lawson, 1999)

Question 6

will change one nucleus to another if the product nucleus has a greater nuclear binding energy than the initial decaying nucleus.

Answer 6

Radioactive decay

Question 7

is the energy required to separate an atomic nucleus completely into its constituent protons and neutrons

Answer 7

Nuclear binding energy

Question 8

Nuclei with an excess of protons or neutrons in comparison with the stable nuclei will decay toward the stable nuclei by changing protons into neutrons or neutrons into protons, or else by shedding neutrons or protons ________

Answer 8

Combination

Question 9

The positive charges of the protons tend to force the protons apart _______

Answer 9

Electromagnetic Force

Question 10

It governs how an unstable nucleus will decay into a stable nucleus. It is responsible for the disintegration in matter.

Answer 10

Weak Force

Question 11

A plot of the number of neutrons versus the number of protons for stable nuclei reveals that the stable isotopes fall into a narrow band. This region is known as the band of stability

Answer 11

Belt of Stability

Question 12

It is a property exhibited by certain types of matter of emitting energy and subatomic particles spontaneously.

Answer 12

Radioactivity

Question 13

It is a property of several naturally occurring elements as well as of artificially produced isotopes of the elements.

Answer 13

Radioactive decay

Question 14

These include long-lived radioactive elements such as uranium, thorium, and any of their decay products, such as radium and radon

Answer 14

Terrestrial Sources

Question 15

• These include nuclear explosives, radioactive fallout from Nuclear Weapon Testing, nuclear reactors, waste from the processing of reactor fuel elements and others

Answer 15

Artificial Sources

Question 16

Also known as decay rate. This refers to the number of times a radioactive decay occurs in the sample per unit time.

Answer 16

Activity

Question 17

It is the activity per unit mass of a substance, whether atoms of a single nuclide or a compound

Answer 17

Specific Activity

Question 18

the amount of time it takes for the decay rate (or count rate) to reach half of its original value

Answer 18

Half-life t1/2

Question 19

life is the amount of time it takes for a given isotope to lose half of its radioactivity

Answer 19

Half-life

Question 20

A type of half-life is defined as the period of time required to reduce the radioactivity level of a source to exactly one half its original value due solely to radioactive decay.

Answer 20

Physical Half-life

Question 21

Is defined as the period of time required to reduce the amount of a drug/pharmaceutical in an organ or the body to exactly one half its original value due solely to biological elimination.

Answer 21

Biological Half-life

Question 22

is defined as the period of time required to reduce the radioactivity level of an internal organ or of the whole body to exactly one half its original value due to both elimination and decay.

Answer 22

Effective Half-life

Question 23

It states that “the probability per unit time that a nucleus will decay is a constant, independent of time.”

Answer 23

Radioactive Decay Law