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physics tests 09
Question | Answer |
---|---|
True or False: Radiographic tables are available in fixed and tilting models | true |
True or False: Compression bands are used to improve radiographic image quality | true |
True or False: The telescoping column of the overhead suspension system controls horizontal movement | false: vertical movement |
magnetic lines of force are referred to as.. | flux lines |
true or false: electromagnets are permanent magnets | false |
an AC generator produces a current that is expressed mathematically as a | sinsusoidal wave |
as the length of a conductor increases the resistance | increases |
as two electrical charges move farther apart, the force between them decrease... | proportionally to the inverse square of their seperation |
True and False: objects can be electrified by induction | true |
the resistance in a wire decreases as its diameter | increases |
when an electric current flows through a wire with resistance, energy is | liberated as heat |
ohms law is mathematically described as | v=ir or r=v/i etc. |
electic insulators | inhbit movement of electical charge |
a volt is a measure of | potential difference |
if the distance between two electrical charges is doubled, the force between them is | decreased by 1/4 |
resistance is | the opposition to the flow of electrons |
if a conductor is postively charged it is | deficient in electrons |
the mA is a unit of | current |
a magnetic field is produced by | electric charges in motion |
a diode electron tube | can be used for rectification |
the process of electrons being emitted from heated metallic surfaces is called | thermionic emission |
a generator is a device that converts | mechanical energy into electical energy |
a simple DC generator has essentially the same construction as a AC generator except that a DC generator has | a commutator |