Ch 6 Notes (Jaubert)
Terms in this set (68)
build up of charges that pass QUICKLY to another object
continuous flow of charges through a conductor
when do objects acquire a static electric charge?
during friction, conduction, and induction
when an object whose electrons are loosely held rubs against another object
when an object with an excess of electrons touches a neutral object
a neutral object acquires a charge from a charged object close by without contact being made
Two balloons rubbed in human hair will become _______ charged and have an attractive interaction with the hair. If the hair is removed, the balloons _______.
the flow of electrons
how does electricity flow?
from high voltage areas to low voltage areas
like electrical pressure that pushes and pulls charges
the push/pull that causes charges to move and is measured in volts (V)
name three ways voltage is created
a chemical cell (battery) when it changes chemical energy to electrical energy
by a generator when it changes mechanical energy to electrical energy
by a solar cell when it changes light energy to electrical energy.
When a wire connects the terminals of a battery or generators, the voltage will push and pull electrons through a ________
One terminal has ______ thus a negative charge. The other terminal has a deficit of electrons and thus a ________.
extra electrons, positive charge
explain what happens to the electrons in the wire
pushed by the negative terminal and pulled by the positive terminal through the wire
a closed, conducting path
For charges to flow, the wire must always be ________
connected in a circuit
the flow of charges through a wire or any conductor.
what is electric current measured in?
current is almost always the _________
flow of electrons
the tendency for a material to oppose the flow of electrons
what does resistance do?
Changes electrical energy into thermal energy and light
give an example of resistance
what is resistance measured in?
what four things affect resistance?
length, cross-sectional area, material, and temperature
what kind of wires would have less resistance?
shorter, fatter wires with higher conductivity and considered T1
what kind of wires would have greater resistance?
longer, skinnier wires with lower conductivity and considered T2
what causes the charges to flow?
flow of charges= ________ (Amps or A)
Electrical resistance restricts the _______ of charges
resistance causes a _______ current
pressure causes a ______ current
what is the formula for current?
current= voltage difference/resistance (Ohm's Law)
label what each letter means in the formula: I=V/R or V=IR
I= current (units= A, amps)
V= voltage (units= V, volts)
R= resistance (units= ohms Ω)
this current has only one loop to flow through
list three facts about a series circuit
- things are wired one right after the other
- If one thing (bulb) goes out every thing goes out
- If the circuit is broken the entire flow of current stops
series circuit: Current is the ______ at each point in the circuit
series circuit: When another resistor (light bulb) is added in series, the ________.
total resistance increases
series circuit: When resistance increases, _________
current will decrease
series circuit: Decreased current means _______.
contains two or more branches for current to move through
parallel circuit: current ________ to flow through the different branches
parallel circuit: because all branches connect the same two points of the circuit - _________
the voltage difference is the same in each branch
parallel circuit: more current flows through the branches that have the ________
In a house, many appliances draw current from _________
the same circuit
If more appliances are connected to a circuit, _________
more current will flow through the wires
More current in wires = _________
more heating in the wires
More heat causes __________, which increases chances of fire
insulation on wires to melt
To protect a house from a fire, all household circuits have what?
a fuse or circuit breaker
a small piece of metal that melts if the current becomes too high
contains a small piece of metal that bends when it gets hot bending causes a switch to flip and opens the circuit
series or parallel: one path for current
series or parallel: multiple paths for current
series or parallel: current is the same at every point
series or parallel: current can be different at each branch
series or parallel: voltage drops at each resistor
series or parallel: voltage same across each resistance
series or parallel: break in circuit stops all current
series or parallel: break in circuit does not affect other bulbs
series or parallel: adding resistance decreases total current (dimmer light bulbs)
series or parallel: adding resistance increases total current
unit for current
unit for power
unit for charge
unit for voltage
unit for time
unit for resistance
what are the three formulas used to find current?
charge/time, voltage/resistance, power/volts