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31 Cards in this Set
- Front
- Back
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What is an 'energy continuum'?
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The wide range of energies existing in an uninterrupted ordered sequence.
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What is a photon?
What is another name for it? |
The smallest quantity of any type of electromagnetic radiation.
A Quantum. |
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What is the speed of light?
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3 x 10⁸ m/s
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What are Sine waves
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Variations of amplitude over a period of time to a discrete mathematical formula.
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What is the symbol for frequency?
How is it defined? |
f or Hz (cycles per second)
The rate of rise and fall of a sine wave. Frequency is equal to the number of times the like parts of a sine wave pass an observed point per unit of time. |
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What is the symbol for wavelength?
How is it defined? |
λ
The distance between two like points on the sinewave. |
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What is the Wave Equation?
How is it written for the speed of light? |
V = fλ
C = fλ |
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What is the electromagnetic spectrum?
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The entire range of electromagnetic radiation.
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What are the regions of the EM spectrum that are important to radiologic technology?
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1. Radiofrequency 10⁶ to 10⁸ Hz
MR Imaging. 2. Visible Light ∽ 10⁻⁶to10⁻⁷ m 3. X-radiation 10⁴ to 10⁵.⁵keV |
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How are energy and frequency of a photon related?
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They are directly proportional.
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Define Refraction.
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The deeviation in the course of visible light when it passes from one transparent medium to another.
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What is infrared light light?
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Photons whose wavelength is longer than visible light but shorter than microwaves.
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What is ultraviolet light?
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Photons whose wavelength is shorter than visible light but longer than ionizing radiation.
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What is the character of RF energy and wave lengths?
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Very low energy and very long wave length.
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Wha is used to characterize ionizing radiation?
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The energy contained in a photon, in keV.
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What is the source of X-rays?
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They are emitted from the electron cloud of an atom that has been artificially stimulated.
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What is the source of Gamma rays?
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They are emitted from the nucleus of a radioactive atom that is undergoing decay.
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What is Wave-Particle Duality?
What is generally true of photon behavior regarding this? |
Photons exhibit both Wave and Particle types of behavior.
Photons interact with matter most easily when the matter is approximately the same size as the photon wavelength. |
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With regard to Wave-Particle Duality, how do X-rays behave?
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Like particles.
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How does EM radiation with wavelength longer than X-rays behave?
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Like waves.
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With regard to visible light, what determines which wavelengths are reflected?
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The atomic and molecular structures of the objects they hit.
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What is radiation attenuation?
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The reduction in intensity resulting from scattering and absorption in the material they are passing through.
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Define radiopaque and radiolucent.
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Radiopaque - the capacity to absorb X-rays.
Radiolucent - the capacity to attenuate X-rays. |
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What is the Inverse Square Law?
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Intensity is inversley proportional to the square of the distance from the source.
I1/I2 = (D2/D1)squared |
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What is the qualifying factor for distance when using the Inverse square Law?
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The distance must be seven times greater than the longest dimension of the source.
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What is the X-ray energy range?
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10keV to 50Mev.
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What is the velocity of X-rays?
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The speed of light.
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What is the relationship of the E and M fields in a photon?
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They both vary sinusoidally with the same frquency and wavelength and are at 90 deg. to each other.
Their amplitudes peak in the middle and diminish at each end. |
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What is the relationship between photon energy and frequency?
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They are directly proportional.
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What is Planck's Constant?
What is its formula? |
The constant of proportionality between photon energy and frequency.
E = Hf H = 4.15 x 10⁻₁⁵ eV = 6.63 x 10⁻₃⁴ J |
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What is the Law of Conservation of Energy?
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Energy can neither be created nor destroyed, but can be transformed.
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