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16 Cards in this Set
- Front
- Back
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What is the most important electron shell? |
The k-shell. The removal of electrons from the k-shell is one way in which x-rays are created. |
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How are electron shells labeled? |
K through Q with k closest to the nucleus, the smallest, the least electrons, and the highest binding energy. |
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Ionization |
The process of a neutral atom gaining or losing an electron. X-rays cause ionization in the atoms of the human body which causes the negative effects of radiation. |
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Ionizing radiation |
Radiation with wavelengths shorter than 1nm which has sufficient energy to remove an electron from its atomic orbit. |
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Photon |
Smallest possible unit of electromagnetic energy |
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Sine wave velocity |
Wavelength x frequency = velocity, all electromagnetic radiation travels at 186,000 miles/sec. |
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Current |
The quantity of electrons flowing in a circuit. Measured in Amperes, A, these units measure the rate, volume, or current flow in the circuit. |
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Potential Difference |
The force or speed of the electron flow in the current. Measured in volts, V. |
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Household circuits |
Operate at around 120V and 15 to 30 Amps |
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X-ray Tube Circuits |
Operate at 40,000 to 125,000 volts (much higher than household) and 0.025 to 0.5 amps (much lower than household use) so we use mA (milliamps) and kVp (kilovoltpeak) instead. |
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Direct Current |
Current flows in one direction from negative cathode to the positive anode. |
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Alternating Current |
Changes directions (polarity) at a particular frequency measured in Hertz. In the US and Canada it is generally 60 Hz or 60 cycles per second. An impulse is half of a cycle, so at 60 Hz there would be 120 impulses. |
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Rectification |
Changing alternating Current so that it flows in one direction only. Rectified DC is pulsating rather than constant like a battery. |
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Step up Transformer |
Has more windings on the secondary (output) side than on the primary (input) side. Multiply the input voltage by the transformer ratio. Ex: 200V in and 500 secondary turns for each primary turn = 500:1 ratio, 200x500=100,000V or 100kVp. |
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Step Down Transformer |
Fewer windings on the secondary (output side) than on the primary (input side) used in xrays to reduce amperage down to milliamps. |
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Relationship between kVp and mA in a transformer |
Inverse relationship |
