CH2 review study questions

What term describes the smallest particle of an element that retains the properties of that element?

Atom

RADIATION

emission/movement of energy through a space

ELECTROMAGNETIC RADIATION

movement of WAVE-LIKE energy through

What subatomic particles carries a negative electric charge?

electrons

Radiant energy sufficient enough to remove an electron from its energy level of an atom is called…?

Ionizing

What term best describes the process by which unstable atoms undergo decay in an effort to obtain nuclear stability?

Radioactivity

All energies of the ELECTROMAGNETIC SPECTRUM share these properties

1. travel at the speed of light

2. no electronic charge

3. no mass

4. pass through space as particles in wavelike motion

5. have energies that are measurable and different

6. emit electrical field at right angles to path of travel

WAVELENGTH

Distance between two similar points of two successive waves (Å)

What electromagnetic radiation has the shortest wavelength?

xrays

What form of radiation has the greatest penetrating power?

xrays

What are the 5 properties of xrays?

1. travel at the speed of light

2. no mass/weight

3. travel in a straight line

4. no electron charge

5. are invisible

FREQUENCY

measure of number of waves that pass a given point of time (Hz)

Short wavelengths are known for …?

• high frequency

• high energy

• more penetrating xray

Xrays generated for the purpose of making a radiographic image are described as …?

Primary radiation

What is most likely the result when dental xrays interact with matter?

compton scattering

What unit is used to measure radiation exposure?

Coulomb per kilogram C/kg (roentgen)

The SI unit that has replaced the international unit REM is …?

Gray, Gy

Diagnostic tests used in medical and dental health care that employ ionizing radiations account for what approximate percentage of the overall total exposure to the US population?

48%

List 3 sources of background radiation

1. Cosmic radiations from space

2. Terrestrial radiations from earth/environments (radon gas)

3. Background radiations from naturally occurring radionuclides (unstable atoms that emit radiations)

What is the average annual amount of background radiation to which the U.S. population is exposed?

3.1 mSv (310 rem)

RADIOPAQUE

white/light grey (DENSE/absorbs and resists xray passage)

• ex -- bone, dentin, enamel

RADIOLUCENT

black/dark grey (LESS DENSE/no resistance)

• ex -- pulp chamber

ex -- pulp chamber

ABSORPTION

disappearance of xray beams passing through matter (weakens/fades away)