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Magnetism
Electromagnetism
Question | Answer |
---|---|
What is the largest magnet? | Earth |
Define magnetism. | material that attracts or repels other materials |
Force | push or pull on an object |
_____ is the SI unit of magnetic strength. | Tesla |
What is magnetic permeability? | ability of a material to attract a magnetic field and become magnetized or east of magnetism. |
How well a material maintains itsmagnetism. | Magnetic retentivity |
What are the 3 classifications of magnets and give one example of each? | natural (earth), artificial (iron -man made), Electromagnet (locks on xray tube or fire doors) |
What are the 4 magnetic classifications of a material? | nonmagnetic; ferromagnetic, paramagnetc, diamagnetic |
Define nonmagnetic. | material that is not affected by a magnetic field |
Define Ferromanetic. | material stongly attracted by magnetic field (ex. iron, cobalt, nickel) |
Define Paramagnetic. | material slightly attracted by a magnet |
Define Diamagnetic. | material weakly repelled by a magnet |
What is a solenoid? | coil of wire carrying a current |
What is an electromagnet? | coil of wire carrying a current with an iron core in coil |
What is a helix? | coil of wire |
Contains a primary coil of wire creating a magnetic field and flow of current with a secondary coil introduced with its own current creating another magneric field. | mutual induction |
Self-induction | coil of wire with constant potential difference (voltage)= unimpeded current flow; uses single coil - autotransformer |
A _______ increases or decreases voltage. | transformer |
A autotransformer is used as the _______. | kVp selector |
Ohm is the unit of measure of _______. | resistance |
An autotransformer works off of mutual electromagnetic induction. T or F | false - self |
The _______ sits on the primary side of the high voltage circuit. | autotransformer |
Anything the RT touches on the control panel is on the _____ side of the high-tension tranformer. | primary |
The step down transformer is used for the ____. | filament circuit (door bell) |
The volt or kilovolt meter is always connected in _____. | parallel |
The ______ is conneced in series. | ammeter |
Converts electrical energy to mechanical energy. | motors (ex. rotor) |
Which device converts mechanical energy to electrical energy? a) motor b) dynamo c) generator | b and c |
Power loss is due to ____.1. varying magnetic field2. heat resistance3. AC current | 2 |
A varying magnetic field leads to ____. | hysteresis loss |
Eddy current loss is due ___.1. varying magnetic field2. heat resistance3. AC current | 3 |
What reduces kV-voltage (6-10v) and increases mA-amps (3-5 amps)? | step down transformer |
If you have a transformer with 500 turns in the primary and 250 turns in the secondary coil, a)what is the turns rtio b)Is it a step up or step down transformer? | a) 250/500= 0.5:1b) step-down transformer |
What is the equation for total power? | P= IV |
If you have a portable viewbox that runs off 220 v and 3 amp, what is the total power requirement? | P=IVP=220(3)P=660 watts |
Like poles _____; unlike poles _____ | repel, attract |
Dipole | every magnet has a north and south pole |
Generator (dynamo) | converts mechanical energy to electrical energy |
Give examples of types of transformers. | air core, open core, closed core, shell type |
What are the two types of transformers? | step up (high tension) or step down transformers |
What are the 3 main causes of power loss? | resistance (loss of power due to heat)hysteresis (loss of power due to changing magnetic field)Eddy current (due to AC) |
Step Up Transformers increase line ______ to kv and decrease _________. | voltage to kV, amperage to mA |
Step Down Transformers dereases kV back to _____ to ______ and increase mA to _______. | 6-10v, heat filament,3-5 amps |
Which has more turns in the 2nd coil?step up or step down transformer | step up transformer |