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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 |

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teachable monkeys