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# Ch 5A Physics

### Electricity

Question | Answer |
---|---|

The Study of stationary electric charges. | Electrostatics |

When an object has too few or too many electrons, it is said to be... | electrified |

3 ways electrification can be created | Contact, Friction, Induction |

A connection that causes electrons to flow from one place to another. | Contact |

The rubbing off of electrons by some kind of object. | Friction |

Magnetic field around charges will interact with each other and push charges to opposite end of the other object. Electrons are grounded as a way to get them out. Involves no touching. | Induction |

Describe Law #1 of Electrostatics | Unlike charges attract, like charges repel. Electric field radiates outward from a positive charge and inward toward a negative charge. |

The force of attraction between unlike charges or repulsion between like charges is due to the electric field. This force is called.... | electrostatic force |

Describe Law #2 of Electrostatics | COULOMBS LAW: The electrostatic force is directly proportional to the product of the electrostatic charges and inversely proportional to the square of the distance between them. F=k(QaQb/d^2) |

Describe Law #3 | How electric charges are distributed: When an object becomes electrified, the electrons spread out over the surface of the object |

Describe Law #4 | Where electric charges concentrate: along the sharpest curvature of the surface (like a cattle prod) |

The force with which electrons travel; the function of difference in number of electrons between 2 points | Potential difference |

The study of electric charges in motion | Electrodynamics |

Any substance through which electrons can flow easily | Conductor |

Any material that does not allow electron flow | Insulator |

A material that under some conditions behaves as an insulator and in other conditions behaves as a conductor. | Semiconductor |

A material or object in which electrons flow very easily. As temperature decreases the resistance decreases. Usually happens at low temperatures. | Superconductor |

According to Ben Franklin, positive charges move towards negative charges which stay put. | Conventional current |

This is created when the resistance of electron flow is controlled and the conductor is made into a closed path. | Electric circuit (measured in Amperes) |

Describe Ohm's law and state the formula | The voltage across the total circuit or any portion of the circuit is equal to the current times the resistance. R=V/I and I=V/R |

In a ____ _____ all circuit elements are connected in a line along the same conductor. | Series circuit |

State the rules for a series circuit | 1. The total resistance is equal to the sum of the individual resistances. 2. The current through each circuit element is the same and is equal to the total circuit current. 3. The total voltage is equal to the sum of the voltages across each circuit. |

A ____ ____ contains elements that are connected at their ends rather than lying in a line along a conductor. | Parallel circuit |

State the rules for a parallel circuit | 1. The sum of the currents thru each circuit is equal to the total circuit current. 2. The voltage across each circuit element is the same and is equal to the total circuit voltage. 3. total resistance=inverse of the sum of the reciprocals of each resis |

List the 4 things that influence resistance | 1. what material the conductor is made of 2. area 3. temperature (less resistance if cooler) 4. length |

What is the function of a radiographic unit? | to convert electric energy into electromagnetic energy |

Give 3 examples of other devices which change the form of energy | Battery, drill, curling iron |

Compare the charge of the electron to the charge of the proton. | Have same magnitude but opposite signs. |

Compare the move-ability of electrons and protons | Protons are fixed in the nucleus, electrons can move from shell to shell of different atoms |

Why does static electricity occur? | Removal of electrons electrifies those substances |

Give 2 examples of static electricity | 1. walking on carpet and touching doorknob 2. combing dry hair |

How many protons are there in the universe | total protons in universe = total electrons in universe |

What is the natural electrical state of all matter | neutral |

what causes a spark | bringing a positively electrified object near a neutral object and some electrons may jump from neutral to positive one |

what is the natural ground | |

how does grounding work | |

compare the initial charge to the end charge in induction electrification | |

what is the smallest unit of electric charge | the electron |

what is the fundamental measurement unit of charge | coulomb |

how many electric charges in 1 coulomb | 1C=6x10618 electron charges |

What is the electric field | field that surrounds each electric charge |

do uncharged particles have electric fields? | no |

what is the unit of force in coulombs law | newtons |

what is the unit of charge in coulombs law | coulomb |

How is the force of attraction/repulsion affected by increasing the magnitude of charge (in Coulombs law) | more force attracting or repelling |

How is the force of attraction/repulsion affected by increasing the magnitude of distance | more force attracting or repelling |

What is the relationship between force and distance in coulombs law | indirect |

what is the relationship between force and charge | direct |

What causes electric potential energy | electric charges can do work when released |

what is the unit of electric potential | volt |

what is a similar name of potential difference | voltage |

How does the size of potential relate to magnitude of voltage | higher voltage, higher potential to do work |

how does the size of voltage relate to the ability to do work | higher voltage, higher potential to do work |

what is the potential for normal household appliances | 110 volts |

define electricity | electric charges in motion |

what causes electrons to move | the application of an electrical current along a conductor |

what is current | flow of electrons |

differentiate between current and charge | current is talking about how many are moving past a point, charge is how negative it is |

what direction do electrons flow | from negative charge to positive charge |

what is the accepted direction of current flow | going toward negative point |

compare current direction to electron flow | current goes toward negative, electron flow goes toward positive |

give 3 examples of a conductor | copper, water, metal |

give 3 examples of insulators | rubber, clay, glass |

give 2 examples of semiconductors | silicon and germanium |

what happens to resistance as temperature increases | it increases |

what happens to resistance to electron flow when the wire diameter increases | resistance decreases |

what is the relationship between resistance and electron flow | indirect |

what is necessary to make electrons move | electric potential energy |

define amperage | number of electrons flowing in the circuit; measures electrical current |

symbol for amperage | I |

unit of electric potential | volts |

symbol for electric potential | V |

unit of resistance | ohms |

Symbol for resistance | R |

what happens to the flow of electrons if the resistance is high | electrons are inhibited from flowing |

what will happen is the voltage is constant and the amperage is increased | the resistance decreases |

define direct current | current in which electrons flow in one direction along the conductor |

define alteranting current | current in which electrons oscillate back and forth |

Created by:
roberts-5691