click below
click below
Normal Size Small Size show me how
Electrostatics
Electrodynamics/Electricity
Question | Answer |
---|---|
Define Electrostatics. | The study of electrons at rest |
Define Electrodynamics. | Electrons in motion (current flow) |
Define electrification. | Gain or loss of electrons from matter. |
Three types of electrification. | Friction, Contact, Induction |
Define friction and state whether or not it confers the same or opposite charge. | rubbing, same charge |
Define contact and state whether or not is confers the same or opposite charge. | touch, same charge |
Define induction and whether or not it confers the same or opposite charge. | No contact between objects, opposite charge |
What is a coulomb? | unit of electric charge |
1 coulomb is equal to how many electric charges | 1 C = 6.3 x 10^18 electric charges |
What is the difference between electrification and ionization? | Electrification is a gain/loss by matter whereas ionization is a gain/loss by an atom. |
Finish this law: Unlike charges__________, like charges _____________ | attract, repel |
Finish this law: Electrostatic force is _____ _____ to the product of the electrostatic charges and ______ proportional to the square of the _______ between them | directly proportional, inversely , distance |
What is the previous law also known as? | Coulomb's |
Finish this law: When an object is electrified,the ______________ | e- are distributed evenly within or outside the object. |
Finish this law: The charge is more concentrated ________________ | along the sharpest curve of the surface. |
Flow of electrons | Current |
What is the unit of measurement of Current? | Amp |
What is a circuit? | Pathway for current to flow (has to be closed to flow) |
What do we use to set our tube current? | mA (1/1000 of amp; milliamps) |
Potential difference is _______. | an excess of electrons at one end and deficiency at the other end |
What is the unit of measurement for potential difference? | voltage |
What do we use to set our potential difference within the tube? | kV,keV,kVp |
kV | kilovolt- average energy |
keV | kiloelectron volts - pot.diff. of each individual electron |
kVp | kilovolt peak - max. potential diff. that you set |
Name four states of matter. | Conductor, insulator, semiconductor, superconductor |
Give an example of a semiconductor. | silicon, germanium, arcelin |
Which state of matter does not allow current to flow due to very high resistance? Give some examples. | insulator (rubber, glass, non-sap wood) |
No resistance, allows free flow of current without potential difference. Cold temps. required. Which state of matter is being described? | superconductor |
Copper, aluminum, silver and gold are examples of what state of matter? | conductor |
Give examples of a superconductor. | niobium, titanium |
Path for current to flow with a potential difference. | Circuitry |
What are the two types of circuitry? | open and closed |
Which circuit does not allow flow of current? | open circuit |
Name five sources where current can come from. | battery, dynamo, solar, atomic, geothermal |
Which source converts mechanical energy into electric energy? | dynamo |
Source that converts chemical energy into electrical energy. | battery |
What are the four conditions in which current will flow? | vacuum, gas, ionic solutions,metallic conductor |
What is resistance? | opposition to current flow |
Wht is the unit of measurement for resistance? | ohm |
what four factors determine resistance? | type of material, length, diameter, temperature |
What material would be considered an insulator or ground? | glass or rubber |
Length and resistance have what kind of relationship | direct-longer the length, more resistance |
Diameter and resistance have what kind of relationship | indirect-smaller the diameter, more resistance |
Temperature and resistance have what kind of relationship | direct-hotter temp. , more resistance |
what are the components of a circuit | *resistiors *battery/energy source *capacitor *ammeter *voltmeter *switch *transformer *rheostat *diode *transistor |
inhibits flow of electrons | resistors |
provides electric potential | battery |
momentarily stores electric charge | capacitor |
measures electric current | ammeter |
measures electric potential | voltmeter |
turns circuit on or off by providing infinite resistance | switch |
increases or decreases voltage by fixed amount (AC only) | transformer |
variable resistor(mA selector) | rheostat |
allows e- to flow in only one direction | diode |
switch that can amplify signals | transistor |
a circuit in which all elements are connected in line along the same conductor | series circuit |
series circuit is measured by what | ammeter |
a circuit that contains elements that bridge conductors | parallel circuit |
parallel circuit is measured by what | voltmeter |
an ammeter measures __________, while a voltmeter measures __________ | *electric current in a circuit(quantity) *potential difference between two points in a circuit(energy) |
What is the formula for Ohm's Law? | V= IR or I= V/R or R= V/I *voltage across the total circuit or any part of the circuit times resistance *I=amperage *v=voltage *R=resistance |
what is the formula for total resistance in a parallel circuit | Rt= R1+R2+R3 |
what is it when electrons flow in one direction only | DC(direct current) *required for xray tube |
what is it when electrons alternate in different directions like sine waves. | AC(alternating current) |
What formula is used to determine total power? | P= IV(I= amperage, V= voltage) |
caused by heat resistance. | Power loss |
What formula is used to determine power loss? | P = I^2*R |