chapter 18-19 Flashcards
electric charge
a property of an object that allows it to be attached or repelled from another charged object
static electricity
the buildup of electric charge on the surface of an object
what is the charge of a proton
+ 1.6 x 10^-19 C
what is the charge of an electron
-1.6 x 10^-19 C
1 Coulomb of charge has ____ electrons
6.25 x 10^18
electrically neutral
equal amounts of positive and negative charge
conductors
objects that allow charges to move freely (ex: metals and salty water)
insulators
objects that do not allow charges to move freely (ex: rubber and wood)
semi-conductors
objects that act as both conductors and insulators depending on the temperature (ex; silicon and germanium)
charges in a conductor will move to the ___ as they can move freely
the surface
charges in an insulator will remain in ___
one place as they can’t move freely
when objects are charged, electric charge is …
transferred between objects; the total amount of charge in the system doesn’t change during this process
turboelectric charging
happens when two charged materials are rubbed against each other transferring charges from one material to the other. This leaves one material with a net positive charge and the other with a net negative charge
charging by conduction
occurs when a charged conductor is placed in contact with a neutral conductor; charges evenly distributed throughout the two conductors
charge by induction
this created a charge in a nearby object without direct contact. the charged object is never touching the object being charged by induction and there is no transfer of charged
polarization
occurs when charge separate but the object remains neutral. through polarization neutral objects can become attracted to a charged object. The object being charged receives a charge opposite that used to charge it
unit for electric field
N/C
electrostatic force
the attraction or repulsion between charges
five rules for electric field lines
- They always point in the same direction as
the electric field at every point - They start at positive charges or infinity
- They end at negative charges or infinity
- The closer the field lines are, the stronger
the electric field - The number of lines that enter or exit a
charge is proportional to the magnitude of the charge
when an electric field is applied to a conductor…
the charges of the conductor move until the field is perpendicular to the surface leaving one side of the conductor positively charged, the other negatively charged. This also created a stronger electric field nearby the conductor and the polarization of charges inside the conductor creates an opposing electric field cancelling any electric field inside the conductor
electric potential energy
the amount of work required to bring a positive test charge close to a negative charge
electric potential
the potential energy per unit charge (unit is Volts)
electric potential difference
occurs when there is a change in electric potential between two points; electric potential difference is also known as voltage
electron-volt
the energy required to accelerate a fundamental charge through a voltage of one volt
the electric potential decreases in the direction of…
the electric field and remains constant in the direction perpendicular to the electric field
electric current
the rate at which charge flows. large currents move a lot of charge in a small amount of time where small current one a small amount of charge in a large amount of time
conventional current travels from…
a higher or positive potential to a lower or negative potential
we use conventional current to define…
the direction that current flows
resistors
impede the flow of current by providing resistance
resistance
the measure of how much a certain material impedes the flow of current
Ohms Law
states that the current traveling in a wire is directly proportional to the voltage across the wire and inversely proportional to the resistance of the wire.
Materials that follow Ohm’s Law are called…
Ohmic Materials and have a linear relationship between current, voltage, and resistance.
Materials that do not follow Ohm’s Law are called…
Non-Ohmic Materials and have an exponential relationship between current, voltage, and resistance
We use Ohm’s Law to determine…
the voltage drop across a resistor in a simple circuit.
A simple circuit consists of…
a battery connected using wires to a resistor.
power
the rate at which energy is used
electrical power
the rate at which electric potential energy is supplied or dissipated
direct current
describes the flow of electric charge in only one direction where voltage and current are always constant
alternating current
describes the flow of oscillating charges that constantly change direction
short circuits
occur when the path current takes is suddenly shortened, increasing the current to an unsafe amount that
increases the temperature of the wi
short circuits
occur when the path current takes is suddenly shortened, increasing the current to an unsafe amount that
increases the temperature of the wire
in an all inseries circuit…
the current is the same for all resistors
in an all in parallel circuit…
the voltage is the same for all resistors
