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Ch 4 RAD 150
Electricity, Magnetism, Electromagnetism
Question | Answer |
---|---|
Primary function of an x-ray imaging system is to convert eletrical energy into _______energy. | electromagnetic |
Unlike charges ____ and like charges ____. | attract; repel |
Coulomb's Law states that electrostatic force is ___ proportional to the product of the electrostatic charges and ____ proportional to the square of the distance between them. | directly; inversely |
Electric charge distribution is ____ throughout or on the surface. | uniform |
Electric charge of a conductor is concentrated along the _____ curvature of the surface. | sharpest |
_____ is the movement of electrons. (electrons moving from one cloud to another) | Induction |
Electrification can be created by ___, ___, or ____. | contact; friction; induction |
The smallest unit of electric charge is the _______. | electron |
1 coulomb is equal to | 6x10 to the (18th) electron charges |
Rubbing a balloon on a wool sweater is an example of _____. | friction |
____ occurs when two objects touch and electrons are transfered between objects. | Contact |
The unit of electric potential is the ____. | volt (V) |
__________ is the study of electric charges in motion. | Electrodynamics |
A ____ is any substance through which electrons flow easily. | conductor |
____, ____ and ____ are three types of insulators. | Glass, clay/earthlike materials, rubber |
A _______ is a material that under some conditions behaves as an insulator and in other conditions behaves as a conductor. | semiconductor |
The ____ is proportional to the number of electrons flowing in the electric circuit. | ampere |
Increasing electric reistance results in a _____electric current. | reduced |
What is Ohm's Law? | V=IR (volts=electric current x electric resistance) |
Resistance (R) is measured in ____. | ohms |
Electric current is measured in ____. | amperes (A) |
_______ is a sine (sinusoidal) curve. | Waveform |
_____ is identified as a 60 hZ current (___ - HZ in the rest of the world). | AC; 50 |
In a ____ ______, electrons can be made to flow in one direction along the conduction. | direct current (DC) |
In a ___ _____, electrons oscillate back and forth. | alternating current (AC) |
A ____ circuit contains elements that are connected at their end rather than lying in a line along a conductor. | parallel |
Electric power is measured in ____. | watts (W) |
In an electric circuit, a ____ will inhibit the flow of electrons. | resistor |
The current through out an entire circuit is ______. | constant |
What is the electric power formula? | P=IV P= power in watts I=current in amps V= electrical potential in volts |
Electrical power is measured in _____. | Watts (W) |
Any charged particle in motion creates a _____ ____. | magnetic field |
_______ objects can be made into magnets by induction. | Ferromagnetic |
An accumulation of atomic magnets with their dipole aligned creates a ____ domain. | magnetic |
The magnetic field is _______ by electron pairs. | neutralized |
The iron core greatly increases the ______ of the magnetic field. | intensity |
What are examples of nonmagnetic states of matter? | wood, glass |
What are examples of diamagnetic states of matter? | water and plastic |
What is an example of a paramagnetic state of matter? | gadolinium |
What are examples of ferromagnetic state of matter? | iron, nickel or cobalt |
______ has low magnetic susceptibility; ____ has high magnetic susceptibility. | Wood; iron |
The SI unit of magnet field strength is the ____. | tesla |
One tesla (T) = ______ gauss (G). | 10,000 |
Like magnetic poles ____ and unlike poles ____. | repel; attract |
The magnetic force is ______ to the product of the magnetic pole strengths divided by the square of the distance between them. | proportional |
A coil of wire is called a ____. | solenoid |
If an electric potential is applied to objects such as copper wire, this would be termed ____ ____. | electric current |
The insulator confines the electron flow to the _____. | conductor |
An object is said to be _______ if it has too few or too many electrons. | electrified |
Theoreticaly, electrons move from _____to _____. | negative; positive |
Resistance is dependent on 4 things: | material, length, diameter and temperature |
The unit for resistance is ____. | ohms |
Theoreticaly, electrons move from _____to _____. | negative; positive |
Resistance is dependent on 4 things: | material, length, diameter and temperature |
Examples of insulators are ____ and ____. | rubber; glass |
The unit for resistance is ____. | ohms |
An example of direct current is a _____. | battery |
The formula for ohms law is: | V=IR |
Examples of insulator are ____ and ____. | rubber; glass |
Examples of a semiconductor are ___ and ____. | silicon; germanium |
Examples of conductors are ___ and ____. | copper; aluminum |
Examples of superconductors are ___ and ___. | niobium; titanium |
A _____ circuit contains elements that are connected at their end rather than lying in a line along a conductor. | parallel |
The increased heat of a wire will _____ conduction. | decrease |
_____ is the best material to conduct electricity. | Copper |
The increased length of a wire will ____ conduction. | decrease |
An increase in diameter will ____ conduction. | decrease |
The unit for electron potential is ______. | volts |
_____ is a material that under some conditins behaves as an insulator and in other conditions behaves as a conductor. | semiconductor |
An example of AC is a _____. | generator |
Two types of magnetic fields: | bipolar and dipolar |
A _____ changes the intensity of alternating voltage and current. | transformer |
_______ turn mechanical energy into electrical energy. | Generators |
What is the Transformer Law? | Vs/Vp=Ns/Np |
What is the Transformer Law Effect on Current? | Is/Ip=Np/Ns |
Step up generator increases voltage and _______ amperage. | decrease |
Step down generator will decrease voltage and _______ amperage. | increase |
What is the formula for turns ratio? | Turns Ratio = Ns/Np |