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What is the law of conservation of matter?
Matter can neither be created nor destroyed.
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What is the law of conservation of energy?
Energy can be neither created nor destroyed.
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What is directly proportional to a photon's frequency?
its energy
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What is one of the substantive statments of Planck's quantum theory?
X-rays are created with the speed of light and they exist with velocity or not at all.
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What is Planck's constant?
Photon energy is directly proportional to photon frequency.
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What are the 4 parameters involved in the inverse square law?
two intensities and two distances
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In Electromagnetic energy, it's decrease in intensity is inversely proportional to the square of the distance of the object from the source is called what law?
Inverse square law
Note: Mr. Penguin says, Electromagnetic energy(radiation) intensity is inversely related to the square of the distance from the source. page 54
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What terms are used routinely in x-ray diagnosis to describe the visual appearance of anatomical structures?
radiopaque and radiolucent
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Structures that transmit x-rays are called?
radiolucent
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Structures that absorb x-rays are called?
radiopaque
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What is absorption?
- Transfer of energy from an electromagnetic field to matter.
- (from the glossary)
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What is transmission?
Passage of an x-ray beam through an anatomical part with no interaction with atomic structures. (from the glossary)
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What is electromagnetic energy attenuation?
Reduction in intensity that results from absorption or scattering.
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Visible light behaves like?
a wave
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A very narrow portion of the enormous spread of the electromagnetic spectrum seen by the human eye is?
visible light
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X-rays behave as though they are?
particles
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When light waves are absorbed, the energy deposited in the absorber reappears as?
heat
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Photons interact with matter most easily when the matter is?
approximately the same size as the photon wavelength
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What is wave-particle duality?
when both visible-light photons or x-ray photons exhibit behaviors of waves and particles.
http://www.youtube.com/watch?v=QNRIeRF8XGg
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How is visible light identified?
visibile light is identified by wavelength
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How is radiofrequency identified?
radiofrequency is identified by frequency (that one's easy)
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How are x-rays identified?
x-rays are identified by energy
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Where are x-ray photons emitted?
the electron cloud of an atom
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Where are gamma rays emitted?
the nucleus of a radioactive atom
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What is the difference between x-rays and gamma rays?
their origin (gamma from nucleus or electron from electron cloud)
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What does RF stand for?
radiofrequency
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What is microwave radiation?
very-short-wavelength RF
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What is refraction?
deviation of the straight line of travel of visible light when it passes through one transparent medium to another
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What is RF(radiofrequency)?
radio waves with relatively low energy and relatively long wavelength
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What waves and rays are included in the electromagnetic spectrum?
radiofrequency, microwaves, infared(IR), visible light, ultraviolet(UV), x-rays and gamma rays
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The energy of a photon is directly proportional to its?
frequency
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Note
In the electromagnetic spectrum, velocity is constant, the wavelength and frequency are inversely related (like a teeter-totter, one goes up the other goes down and vice versa).
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In the electromagnetic spectrum, what are the three regions most inportant to radiologic science?
- visible light
- x- and gamma radiation
- radiofrequency(RF)
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The electromagnetic spectum includes....
the entire range of electromagnetic energy
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As the frequency of electromagnetic energy increases.....
the wavelength decreases
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What is the wave equation?
a simple mathmatical formula that expresses the interrelationship of velocity, wavelength and frequency
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The wave equation is used for.....
both sound and electromagnetic energy
velocity = frequency x wavelength
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Note: Sound waves are very different from electromagnetic photons.
The sources of sound are propagated in different ways and their volocities vary greatly. The velocity of sound depends on the density of the materal through which it passes. Sound cannot travel through a vacuum.
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Note: Because velocity is always constant in electromagnetic energy (the speed of light) the electromagnetic wave equation is used.
velocity of light(c) = frequency x wavelength
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At a given(set) velocity, wavelength and frequency are....
inversely proportional.
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In sine waves, as the velocity decreases the frequency....
decreases proportionately.
Remember, velocity of electromagnetic energy is always constant(speed of light) so when the book talks about decreased velocity it is not talking about electromagnetic energy.
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What is wavelength (λ) ?
the distance from one crest to another, from one valley to another, or from any point of the sine wave to the next corresponding point
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What is frequency (f)?
- the number of crests or valleys that pass a point of observation per second (cycles per second)
- the rate of rise and fall
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Frequency is measured in?
- hertz(Hz)
- one hertz is equal to one cycle per second
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What is Amplitude?
one-half the range from crest to valley over which the sin wave varies.
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What is a sine wave?
variations of amplitude over time
can be described by a mathmatical formula and therefore have many applications in physics
dictionary- smooth repetitive oscillation (sinusoidal)
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What is another name for a photon?
quantum
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What is the velocity of electromagnetic energy?
the speed of light(c)
3 x 10ᶺ8
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What is electromagnetic energy?
energy that has both electric and magnetic properties
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What is a continuum?
an uninterrupted(continous) ordered sequence
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A photon is the smallest quantity of any type of...
electromagnetic energy
Note: A photon may be pictured as a small bundle of energy, sometimes called a quantum, that travels through space at the speed of light.
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What is a field ?
- term used to describe interactions among different energies, forces, or masses
- Example: gravitational field, we know it exists because it holds us to the earth even though we can't see it
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What diagnostic tool is not part of the electromagnetic spectrum?
ultrasound
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