electricity Flashcards
what is the SI unit used to measure electrical charges?
6.25x10^18 electrons
We use a measure of electrons because electricity is most often due to their movement because __________________________________
protons are fixed to their position inside the nucleus
can be used to describe the attraction and repulsion between any charged particles, including atomic particles
Coulomb’s Law
Coulomb’s Law follows the _______________
inverse square law
in Coulomb’s Law, Q1 and Q2 are _______________
quantities (electrostatic charges)
in Coulomb’s Law, r is the _____________
distance
in Coulomb’s Law, k is the ____________-
electrostatic constant (9.0 x 10^9Nm^2/c^2)
5 laws of electrostatics
- Like charges repel, unlike charges attract
- Coulomb’s Law (the force of attraction or repulsion is a function of the square of their distance)
- Electric charges reside only on the outside surface of conductors
- The concentration of charges on a curved surface is greatest where the curvature is greatest
- Only negative charges (electrons) are free to move
when objects gain either a net positive or net negative charge
electrification
3 modes of electrification
friction, contact, induction
electrification in which electrons are rubbed away from one object and deposited on another
friction
shuffling your feet on carpet is an example of what?
electrification via friction
electrification in which when a charged object touches an uncharged object which then acquires the same charge
contact
a shock when your finger touches a doorknob is an example of what?
electrification via contact
electrification in which an uncharged metallic object experiences a shift in electrons when it is brought into the electric field of a charged object
induction
charging an electric toothbrush is an example of what?
electrification via induction
for electrical current to move, there must be an __________________
electric potential
electric potential is measured in ___________
voltage or J/C
A volt is defined as the potential difference that will maintain _________________ in a circuit with the resistance of ______
a current of one ampere, one ohm
SI unit for energy
joules
V = _________
J/C
J = ___________
(V)(C)
-A volt is _________________
-A current is ___________________-
-the difference in electric potential between two charges that makes current flow
-the actual flow of electrons
Electric current exists when two conditions are met
1. There must be ______________________
2. There must be ____________________-
- an electric potential difference between two charges
- a suitable medium through which to travel (conductor)
metals or substances with free electrons that allow the flow of a current.
conductors
Good conductors have electrons that (are/are not) tightly bound to their atoms.
are not
These electrons are then replaced by electrons from other atoms in a chain reaction that moves towards the ______ end of the potential
positive
