RT 110 physics test
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What is the wave equation?
Velocity = frequency x wavelength
If frequency increases, then wavelength _______
If frequency decreases, then wavelength _________
What is defined as the number of wave forms per second?
Frequency is a representation of _______
X-ray photons are about __ cycles per second
As beam energy is increased, frequency ______
Beam energy is determined by what?
The higher the kVp, the _____ the ________ (there are 4)
- the higher the photon frequency
- the higher the beam quality
- the harder the beam
- the higher the penetrability of the beam
Higher energy photons act like what?
- note: if they hit something, they do damage
Low energy photons act like what?
- note: they just bump into things. takes a lot to do damage
An electric current is induced in a circuit if part of the circuit is in a changing magnetic field. A magnetic field can be generated by alternating magnetic fields. This is known as what?
Transformers work with __ current through the application of Faraday's Law.
The goal of a step-down transformer is?
- To decrease the incoming voltage and increase current.
- ***They work on the principle of mutual induction
- ***Allows for thermionic emission to occur at the filament
- ***Ultimately, provides the electrons necessary for x-ray production.
Which side of the step-down transformer has fewer windings?
The goal of a step-up transformer is?
To increase the voltage
Which side of the step-up transformer has more wires?
- Secondary side
- ***therefore a higher voltage is produced
Which side of the step-up transformer does the voltage come in?
What are 2 other names for the step-up transformer?
What has only one winding and works on the principle of self-induction?
What are the 3 types of transformers?
- Closed-core transformer
- Autotransformer (single)
- Shell-type transformer
What gets transformed in a transformer?
Voltage and current
What are the 3 sections of the x-ray circuit
- Operating (control) console
- High voltage generator
- X-ray tube
What addresses the issue of the divergent beam?
- Inverse Square Law
- ***As the beam travels it diverges or spreads out. The further it travels the more spread out it becomes, however, the intensity will be diminished
What are conditions that are necessary for x-ray production?
- High voltage-in the kilovolt range
- Electrons-a supply of electrons and a need to stop the electrons suddenly
How do transformers work?
- The can only work using AC current
- On the principle of induction - mutual and self
- The basic premise is that the AC current "induces" alternating magnetic fields in loop (coils) of wire
- These alternating magnetic fields are distributed throughout the core of the transformer
What is the conservation of energy?
When voltage is increased, the current decreases
Which side of the step-down transformer has more coils?
- The primary side
- ***This results in a decrease in voltage through the transformer
What consists of the operating (control) console?
- Line voltage compensator/monitor
- kVp selector
- mA selector
- Pre-reading kVp meter
What is the purpose of the line voltage compensator?
To maintain a constant voltage to the system. In the modern system this is done automatically
The autotransformer works on what principle? Is it a step- up or step-down transformer or both?
- The autotransformer works on the principle of self-induction. It has a single core and is responsible for varying the voltage.
- Because of its ability to adjust voltage, the autotransformer can be either a step-up or step-down transformer.
Where is the kVp adjusted at?
Why is the kVp meter considered pre-reading?
- •The kVp meter is considered pre-reading because it is not actually measuring kVp but measuring voltage off the autotransformer.
- ***Remember, the autotransformer is used to adjust voltage.
What types of electronic timers are out there as of today?
- Phototiming (AEC)
- Regular electronic
What does the mA selector do?
- Allows for adjust of the filament voltage
- ***Precision resistors
- ***Choke coil
What is another name for the step-down transformer?
What is the purpose of the retifier?
To allow electrons to flow in only one direction
How many retifiers are required to fully convert AC to DC?
Rectifiers convert __ to __ current
AC to DC current
What are the types of circuits?
- Single phase
- Three phase
- Medium and high frequency
- Capacitor discharge
What consists of the single phase?
What consists of the three phase?
What do the three phase units use for transformers?
Delta and 'wye'
In a three phase transformer, the 6 pulse uses what and how many transformers?
2 'wye' and 1 delta
In a three phase transformer, the 12 pulse uses what and how many transformers?
2 delta and 1 'wye'
Three phase transformers require how many rectifiers?
What are the advantages of three phase?
- Higher beam quantity and quality
- Higher mA stations are also possible
Why higher quantity and quality for three phase?
- Because the voltage ripple is less
- ***Basically when the tube is energized it stays energized.
The turns ratio for the step-up transformer is:
500:1 or 1000:1
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