PART ONE - CHAPTER 3 AND CHAPTER 4

CHAPTER 3 AND CHAPTER 4

electromagnetic energy

every present all around us is a state of energy called ________

energy continuum

every present all around us is a state of energy called electromagnetic energy. This energy exist over a wide range called an __________.

continuum

a _______ is an uninterrupted (continuous) ordered sequence.

photon

a _______ is the smallest quantity of any type of electromagnetic energy.

atom

_____ is the smallest quantity of an element

quantum

a photon may be pictured as a small bundle of energy, sometimes called a ______, that travels through space at the speed of light.

xray photon

an _______ is a quantum of electromagnetic energy.

3 × 10 ^8 m/s

the velocity of all electromagnetic radiation is ______

amplitude

_______ is one-half the range form crest to valley over which the sine wave varies.

frequency

_______ is the number of wavelengths that pass a point of observation per second.

wavelength

The _________ is the distance from one crest to another, from one valley to another or from any point on the sine wave of three different wavelengths.

constant

velocity is ________ (constant or not constant)

1. velocity

2. frequency

3. wavelength

these are the three wave parameters need to describe electromagnetic energy.

wave equation

______ this brief analogy demostrates how the three parameters associated with a sine wave are interrelated.

sound and electromagnetic

the wave equation is used for both ____ and ________ energy

10² to 10²⁴ Hz

the frequency range of electromagentic energy extends from approximately _________

electromagnetic spectrum

The ________ includes the entire range of electromagnetic energy.

1. Visible light

2. xray and gamma radiation

3. RF

The known electromagnetic spectrum has three regions most important to radiologic science:

diagnostic ultrasound

____________ is not a part of the electromagnetic spectrum

directly proportional

the energy of a photon is ____________ to its frequency

century

the electromagnetic spectrum has bee scientifically investigated for longer than a _______

Refraction

although photons of visible light travel in straight lines, their course can be deviated when they pass from one transparent medium to another. This deviation in line of travel, called ______, is the cause of many peculiar but familiar phenomena.

400 nm for violet to 700 nm for red

The components colors of white light have wavelength values ranging from approximately __________ and __________

visible light

_______ occupies the smallest segment of the electromagnetic spectrum, and yet it is the only portion that we can sense directly.

infared and ultraviolet

sunlight also contains two types of invisible light: _______ and ______

infared lights

________ consists of photons with wavelengths longer than those of visible light but shorter than those of microwaves.

infarred light

______ heats any substance on which it shines. It may be considered radiant heat

ultraviolet light

________ is located in the electromagnetic spectrum between visible light and ionizing radiation.

ultraviolet light

it is responsible for molecular interactions that can result in sunburn.

radiofrequency emissions

communication broadcasts are usually identified by their frequency of transmission and are called _________

radio - frequency

________ has relatively low energy and relatively long wavelength

microwave radiation

very short wavelength RF is _____________

Microwave

________ vary according to use but are always higher than broadcast RF and lower than infared.

origin

The only difference between x-rays and gamma rays is their ______

xrays

_____ are emitted from the electron cloud of an atom that has been stimulated artificially

Gamma rays

_________ come from inside the nucleus of a radioactive substance

nucleus

beta particles from from the ________

electrons

_________ come from outside the nucleus

wavelength

Visible light is identified by________

frequency

radiofrequency is identified by _______

energy

xrays are identified by _______

visible light region

The _________ is also important because the viewing conditions of a radiographic or fluoroscopic image are critical to diagnosis.

Visible-light photons

____________ tend to behave more like waves than particles.

wave-particle duality

Visible-light photons tend to behave more like waves than particles. The opposite is true of x-ray photons, which behave more like particles than waves. In fact both types of photons exhibit both types of behavior— a phenomenon known as the ________ of electromagnetic energy

Photons

__________ interact with matter most easily when the matter is approximately the same size as the photon wavelength.

wavelength

Another general way to consider the interaction of electromagnetic radiation with matter is as a function of _____________.

antennas

Radio and TV waves, whose wavelengths are measured in meters, interact with metal rods or wires called _______

nanometers (nm)

The wavelength of visible light is measured in _____________

wave phenomenon

All radiation with a wavelength longer than those of x-radiation interacts primarily as a ______________.

particles

xrays behave as though they are __________

visible light

It is interesting that we have developed organs that sense only a very narrow portion of the enormous spread of the electromagnetic spectrum. This narrow portion is called ___________

visible-light spectrum

The ____________ extends from short wavelength violet radiation through green and yellow to long-wavelength red radiation.

Visible light

____________ behaves like a wave.

Electromagnetic energy attenuation

___________ is the reduction in intensity that results from scattering and absorption.

Reflection

_________ from the silvered surface of a mirror is common.

radiopaque and radiolucent

The terms________ and ____________ are used routinely in x-ray diagnosis to describe the visual appearance of anatomical structures.

radiopaque

Structures that absorb x-rays are called _______

radiolucent

structures that transmit xrays are called _________

inverse square law

This decrease in intensity is inversely proportional to the square of the distance of the object from the source. Mathematically, this is called the________

reduction of wave amplitude with distance from the source.

The reason for the rapid decrease in intensity with increasing distance is that the total light emitted is spread out over an increasingly larger area. The equivalent of this phenomenon in the water wave analogy is the _______.

fixed

in inverse square law, the wavelength remains ___________.

inverse square law

The intensity of electromagnetic radiation is inversely related to the square of the distance from the source.

seven times

The inverse square law can be applied to distances greater than ______ the longest dimension of the source.

xrays

______ are usually identified by their energy, measured in electron volts (eV)

10 keV to 50 MeV

X-ray energy ranges from approximately __________.

x-ray photon

An _____ can be thought of as containing an electric field and a magnetic field that vary sinusoidally at right angles to each other with a beginning and an end that have diminishing amplitude

wave equation.

The frequency of an x-ray photon is calculated similarly to the frequency of any electromagnetic photon, with use of the________

xray photon

The _______ is a discrete bundle of energy.

Max Planck

_______ was a German physicist whose mathematical and physical theories synthesized our understanding of electromagnetic radiation into a uniform model; for this work, he received the Nobel Prize in physics in 1918.

frequency

The energy of a photon is directly proportional to its ________.

photon frequency

Photon energy is directly proportional to ________.

Planck’s constant

The constant of proportionality, known as ___________ and symbolized by h, has a numeric value of 4.15 × 10−15 eVs or 6.63 × 10−34 Js.

matter

______ can be neither created nor destroyed, a law known as the law of conservation of matter.

law of conservation of matter

matter can be neither created nor destroyed, a law known as the _________

law of conservation of energy

A similar law, the_____________, states that energy can be neither created nor destroyed.

pair production

Nuclear fission, the basis for generating electricity, is an example of converting matter into energy. In radiology a process known as ___________

electric energy into electromagnetic energy

The primary function of an x-ray imaging system is to convert ______________.;

well-controlled electric current.

electric energy is supplied to the x-ray imaging system in the form of ___________

x-ray tube

A conversion takes place in the_________, where most of this electric energy is transformed into heat, some of it into x-rays.

electric motor

Electric energy is converted into mechanical energy with a device known as an __________, which can be used to drive a circular saw.

positive or negative

Electric charge comes in discrete units that are _______ and ________.

Electrons and protons

________ and __________ are the smallest units of electric charge.

negative charge

The electron has one unit of _________

positive charge

proton has one unit of __________

Electrostatics

___________ is the study of stationary electric charges.

Protons

__________, on the other hand, are fixed inside the nucleus of an atom and are not free to move.

electrons

Because of the way atoms are constructed, ________ often are free to travel from the outermost shell of one atom to another atom.

• contact

• friction

• induction.

Electrification can be created by______, ______, and _________.

static electricity

Removal of these electrons electrifies the substances from which they were removed and results in ___________

electric ground.

One object that is always available to accept electric charges from an electrified object is the Earth. The Earth behaves as a huge reservoir for stray electric charges. In this capacity, it is called an ________

electrostatic laws

unlike charges attract; like charges repel

electric field.

associated with each electric charge is an _______

repel each other.

When two similar electric charges—negative and negative or positive and positive—are brought close together, their electric fields are in opposite directions, which cause the electric charges to _______

electrostatic force

The force of attraction between unlike charges or repulsion between like charges is attributable to the electric field. It is called an __________

electrostatic force

The ________ is very strong when objects are close but decreases rapidly as objects separate.

sharpest curvature

Electric charge of a conductor is concentrated along the _________ of the surface.

“Our business is shocking”

___________ is the motto of the manufacturer of the leading cattle prod

potential energy

Electric charges have__________

volt (V)

The unit of electric potential is the_______

voltage

Electric potential is sometimes called _______