Electromagnetic Energy Week 3

A photon is

neutral bundle of energy

A photon can act

particle and a wave

How are radio wavelengths measured?

Km (Kilometers)

Gamma rays are

highly penetrating (based on frequency)

Wavelength is measured

peak to peak

Higher wavelength frequency means

higher energy

shorter wavelengths

Lower wavelength frequency means

lower energy

longer wavelengths

Electromagnetic energy

travels through space as a combination of electric and magnetic fields

Direction of photon travels

speed of light

EM (electromagnetic energy) radiation is measured

speed of light in a vacuum (no interference)

Sine waves frequencies are measured in

1 second

Symbol for wavelength

λ (lambda)

Velocity (v) =

frequency x wavelength

Basic wavelength equation

c = vλ

What does the “c” in c = vλ represent?

constant (speed of light) (3×10^8 m/s)

Frequency means

number of times per second crest passes a certain point per second (cycles per second)

Equation for photon energy?

E = h x f

What does the “E” in E = h x f represent?

photon energy (ev)

What does the “h” in E = h x f represent?

Planks constant (4.15 × 10^-15 ev/s)

Hertz (Hz) or cycles per second

Unit of frequency

What is Angstrom?

unit of wavelength for an x-ray (10^-10 m or 0.1 nanometer)

How do you convert a nm to m?

multiply by 10^-9

Electromagnetic waves differ from ocean waves because

don’t need a medium, travel in a vacuum

What is Wave-Particle Duality?

When high frequency electromagnetic energy interacts with matter, it behaves more like a particle than a wave

What is Particle Theory?

Photon energy and frequency are directly proportional

• if the frequency increases, photon energy increases

What are the Proportional Relationships?

Directly Proportional

• As you increase frequency, photon energy increases

Inversely Proportional

• As you increase frequency, wavelength decreases

What is the Inverse Square Law?

All EM (electromagnetic energy) radiation diverges from a source when it’s emitted, spreading the intensity of the radiation over a larger area

(Characteristics of X-Rays) Have no

mass

(Characteristics of X-Rays) Highly

penetrating / Invisible

(Characteristics of X-Rays) Electrically

neutral

(Characteristics of X-Rays) Poly / Hetero

Polyenergetic / Heterogeneous

(Characteristics of X-Rays) Travel

in straight lines (as a wave) at the speed of light ( 3 × 10⁸m/s)

(Characteristics of X-Rays) Can

ionize matter

(Characteristics of X-Rays) Produce biologic

changes in tissues

(Characteristics of X-Rays) Produce

scatter

What is the Electromagnetic Spectrum?

The complete spectrum (or continuum) of all forms of “light”

(The electromagnetic spectrum) First

radio waves

(The electromagnetic spectrum) After radio waves?

cell phone waves

(The electromagnetic spectrum) After cell phone waves?

microwaves

(The electromagnetic spectrum) After microwaves?

radar waves

(The electromagnetic spectrum) After radar waves?

infrared waves

(The electromagnetic spectrum) After infrared waves?

visible light waves

(The electromagnetic spectrum) After visible light waves?

ultraviolet waves

(The electromagnetic spectrum) After ultraviolet waves?

x-ray waves

(The electromagnetic spectrum) After x-ray waves?

gamma waves

Which color has the lowest frequency?

red

Which color has the highest frequency?

violet

How can you remember the order from lowest to highest color frequency?

ROY G BIV