Atoms

Question 1

Matter

Answer 1

Anything that occupies space and has mass.

Question 2

Nucleus

Answer 2

The central, positively charged core of an atom; composed of protons and neutrons.

Question 3

Protons

Answer 3

A positively charged particle with a mass of one.

Question 4

Neutrons

Answer 4

An electrically neutral or uncharged particle.

Question 5

Electrons

Answer 5

A tiny negatively charged particle found outside of the nucleus in the atom.

Question 6

Electrostatic force OR binding energy

Answer 6

The attraction between the positive nucleus and the negative electrons that maintains electrons in their orbits.

Question 7

Molecule

Answer 7

Two or more atoms joined together by chemical bonds.

Question 8

Velocity

Answer 8

The speed of a wave

Question 9

Wavelength

Answer 9

The distance between the crest of one wave to the crest of the next wave; determines the energy and penetrating power of the radiation.

• Shorter the wavelength, the higher the energy
• Longer the wavelength, the lower the energy

Question 10

Frequency

Answer 10

The number of wavelengths that pass a given point in a certain amount of time; frequency indicates the energy of a radiation.
(Higher frequency radiations have more energy than low frequency radiations)

Question 11

Control panel

Answer 11

A part of the dental X-ray machine that contains an on-off switch and an indicator light, an exposure button and indicator light, and control devices to regulate the x-ray beam.

Question 12

Extension arm

Answer 12

A part of the dental X-ray machine; suspends the x-ray tubehead and houses electrical wires that extend from the control panel to the tubehead.

Question 13

Tubehead

Answer 13

The tightly sealed heavy metal housing that contains the dental X-ray tube.

Question 14

Compton scatter

Answer 14

One of the interactions of x-radiation with matter in which the X-ray photon collides with a loosely bound, outer shell electron and gives up part of its energy to eject the electron from its orbit. The x-ray photon loses energy and continues in a different direction at a lower energy level.

Question 15

Coherent scatter

Answer 15

One of the interactions of x-radiation with matter in which the path of an low-energy x-ray photon interacts with an outer-shell electron. No change in the atom occurs, and an x-ray photon of scattered radiation is produced (also known as unmodified scatter).

Question 16

Cathode

Answer 16

The negative electrode in the x-ray tube; consists of a tungsten wire filament in a molybdenum cup; supplies the electrons necessary to generate x-rays.

Question 17

Anode

Answer 17

The positive electrode in the x-ray tube; consists of a wafer-thin tungsten plate embedded in a solid copper rod; converts electrons into x-ray photons.

Question 18

Primary radiation

Answer 18

The penetrating X-ray beam produced at the target of the anode and exits the tubehead.

Question 19

Secondary radiation

Answer 19

Radiation created when the primary beam interacts with matter.

Question 20

Scatter radiation

Answer 20

A form of secondary radiation; results form an X-ray beam that has been deflected from its path by the interaction with matter.

Question 21

Radioactivity

Answer 21

The process by which certain unstable atoms or elements undergo spontaneous disintegration, or decay, in an effort to attain a more balanced nuclear state.