RT 203 MODULE 3: ELECTRICITY AND MAGNETISM

PHOTON

• First described by ancient Greeks

• The smallest quantity of any type of electromagnetic energy

ELECTROMAGNETIC ENERGY

Today, photons are known as

QUANTUM

Pictured as a small bundle of energy called a

JAMES CLERK MAXWELL

• 19th century

• both electric and magnetic properties

• hence the term electromagnetic energy

• VELOCITY

• AMPLITUDE

• WAVELENTH

• FREQUENCY

PROPERTIES OF ELECTROMAGNETIC ENERGY

Velocity

Photons are considered as energy disturbances that move through space at the speed of light

Speed of light

• 3 X 10 ^8 m/s

• 186,000 mi/s

Amplitude

They have electric and magnetic fields that are continuously changing in a sinusoidal fashion

One - half

Is the range from crest to valley over which the sine wave varies

no mass and no identifiable form

Photons have ?

Amplitude

Crest

What is number 1?

Valley

What is number 2?

WAVELENTH

• The distance of one crest to another, from one valley or any from any point on the sine wave to the next corresponding point

• Greek letter lambda λ

SINE WAVE

It is the model of EM energy describes variations in the electric and magnetic fields as the photon travels with velocity c

lambda λ

What represents a Greek letter

FREQUENCY

• the number of crests or the number of valleys that pass the point of an observer per unit of time

• The rate of rise and fall of the sine waves

hertz (Hz)

what is the unit of frequency measurement

CYCLES PER SECOND

frequency is identified as

WAVE PARAMETERS

• Velocity, Frequency, and wavelength

• A change in one affects the value of the others

Constant

In Wave Parameters Velocity is?

INVERSELY PROPORTIONAL

At a given velocity, wavelength and frequency are

WAVE EQUATION

Sound waves differ from electromagnetic energy by how they are propagated and their velocity varies greatly

sound and electromagnetic energy.

What is the use of Wave equation

Wave Equation

What formula is this?

INVERSELY PROPORTIONAL

Electromagnetic energy, frequency and wavelength are?

• 186,000 mi/s

• 3X10^8 m/s

C

Looking for wavelength

Looking for frequency

Looking for Speed

ELECTROMAGNETIC SPECTRUM

• Group of different types of electromagnetic energies

• Includes the entire range of electromagnetic energy

10² to 10^24 Hz

Frequency ranges from

10^7 to 10^-16m

Wavelength ranges from approximately

VISIBLE LIGHT

Red, Orange, Yellow, Green, Blue, Indigo, and Violet

• Longer wavelength

• Lower frequency

• Lower energy

Radio wave, Microwave, and Infrared are considered as?

• Shorter wavelength

• Higher frequency

• Higher energy

Ultraviolet, Xrays and Gamma Rays are considered

IONIZING RADIATION

Ultraviolet, Xrays and Gamma Rays they are also classified as

NON IONIZING RADIATION

Radio wave, Microwave, and Infrared are also classified as a

eV

Electron Volts or Energy

Hz

Hertz or Frequency

m

Wavelength

MeV

Mega electron Volts

1 MeV

10^6

1 nm

10^-9m

1 KeV

10³

1 eV

neutral 10^0

Energy group (eV)

1 MeV

1 KeV

1 eV

MeV

Megaelectron volts

KeV

Kiloelectron volt

1 GHz

10^9

1 MHz

10^6

1 KHz

10³

Frequency group (Hz)

• 1 GHz

• 1 MHz

• 1 KHz

GHz

GigaHertz

MHz

MegaHertz

KHz

KiloHertz

1 km

10³

1 m

10 as constant

1 cm

10^-2

1 μm

10^-6

1 nm

10^-9

Wavelegnth (m) group

• 1 nm

• 1 μm

• 1 cm

• 1 m

• 1 km

km

kilometer

m

meter

cm

centimeter

μm

micrometer

nm

nanometer

• Visible light

• Radiofrequency

• X-ray Radiation

• Gamma Radiation

Regions important to Radiologic Science

Diagnostic Ultrasound

is not part of the electromagnetic spectrum?

Ultrasound

is not produced in photon form and does not have a constant velocity

EM can exist in a vacuum

Diagnostic Ultrasound is not part of the electromagnetic spectrum because what does it required a matter to propagate?

Visible Light

• Identified by wavelength

• Occupies the smallest segment of the electromagnetic spectrum yet it’s the only portion we can sense directly

• Wavelengths

700 nm

What is red, orange, yellow?

400 nm

what is green, blue, violet?

RADIOFREQUENCY RANGE

• Identified by frequency

• Covers a considerable portion of the electromagnetic spectrum.

• Relatively low energy and relatively long wavelength.

X-RADIATION AND GAMMA RADIATION

• Identified by energy.

• Used to be differentiated based on their energy ranges.

• Due to technological advancements, they are now differentiated through their origins

XRAYS

GAMMA RAYS

WAVE-PARTICLE DUALITY

• Electromagnetic wave behaves like a particle or vice versa.

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

• RF with wavelengths measured in meters interact with antennas.

• Microwaves with wavelengths measured in centimeters interact with hotdogs or hamburgers

• Visible light with wavelength measured in nanometers interacts with living cells such as the rods and cones of the eye.

• UV light interacts with molecules

• X-radiation interacts with electrons and atoms.

• In general, all electromagnetic radiation with wavelength longer than those of x-radiation interacts primarily as a wave phenomenon.

VICE VERSA

Electromagnetic wave behaves like a particle

TRUE

Photons interact with matter most easily when the matter is approximately the same size as the photon wavelength?

ANTENNAS

RF with wavelengths measured in meters interact with

HOTDOGS OR HAMBURGERS

Microwaves with wavelengths measured in centimeters interact with

RODS AND CONES OF THE EYE

Visible light with wavelength measured in nanometers interacts with living cells such as the

X-RAY RADIATION

interacts with electrons and atoms

MOLECULES

UV light interacts with

WINDOW GLASS

TRANSPARENT

FROSTED GLASS

TRANSLUCENT

BLACK GLASS

OPAQUE

ATTENTUATION

reduction in intensity that results from scattering and absorption

WAVE MODEL:VISIBLE LIGHT

• Visible light behaves like a wave Interactions of visible light with matter

• Reflection

• Transmission

• Absorption

• Attenuation

RADIOPAQUE

Structures that absorb x-ray are called

RADIOLUCENT

Structures that transmit x-rays are called

ANATOMICAL STRUCTURES

The terms radiopaque and radiolucent are used routinely in x-ray diagnosis to describe the visual appearance of ?

PARTICLE MODEL: QUANTUM THEORY

• X-rays behave as though they are particles.

• X-rays are identified by their energy, measured in

electron volts (eV).

• X-ray energy ranges from approximately 10 keV to 50

MeV with wavelengths ranging from

approximately 10^−10 to 10^−14 m and frequencies

ranging from approximately 10^18 to 10^22 Hz.

MAX PLANCK’S QUANTUM THEORY

Photons are created with the speed of light (c), and they

exist with velocity (c) or they do not exist at all

DIRECTLY PROPORTIONAL

This theory also dictates that “the energy of a photon is ______________? to its frequency

what is number 1

Electric field

Speed of light

What is number 2?