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Ch 6 Notes (Jaubert)
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Gravity
Terms in this set (68)
build up of charges that pass QUICKLY to another object
static electricity
continuous flow of charges through a conductor
electric current
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
friction
when an object with an excess of electrons touches a neutral object
conduction
a neutral object acquires a charge from a charged object close by without contact being made
induction
Two balloons rubbed in human hair will become _______ charged and have an attractive interaction with the hair. If the hair is removed, the balloons _______.
negatively, repel
the flow of electrons
electricity
how does electricity flow?
from high voltage areas to low voltage areas
like electrical pressure that pushes and pulls charges
voltage
the push/pull that causes charges to move and is measured in volts (V)
voltage difference
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 ________
conductor
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
circuit
For charges to flow, the wire must always be ________
connected in a circuit
the flow of charges through a wire or any conductor.
electric current
what is electric current measured in?
Amperes (A=Amps)
current is almost always the _________
flow of electrons
the tendency for a material to oppose the flow of electrons
resistance
what does resistance do?
Changes electrical energy into thermal energy and light
give an example of resistance
lightbulb filament
what is resistance measured in?
Ohms (Ω)
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?
a voltage
flow of charges= ________ (Amps or A)
current
Electrical resistance restricts the _______ of charges
movement
resistance causes a _______ current
lower
pressure causes a ______ current
higher
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
series circuit
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
same
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 _______.
dimmer light
contains two or more branches for current to move through
parallel circuit
parallel circuit: current ________ to flow through the different branches
splits up
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 ________
lower resistance
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
fuse
contains a small piece of metal that bends when it gets hot bending causes a switch to flip and opens the circuit
circuit breaker
series or parallel: one path for current
series
series or parallel: multiple paths for current
parallel
series or parallel: current is the same at every point
series
series or parallel: current can be different at each branch
parallel
series or parallel: voltage drops at each resistor
series
series or parallel: voltage same across each resistance
parallel
series or parallel: break in circuit stops all current
series
series or parallel: break in circuit does not affect other bulbs
parallel
series or parallel: adding resistance decreases total current (dimmer light bulbs)
series
series or parallel: adding resistance increases total current
parallel
unit for current
amps
unit for power
watt
unit for charge
coulomb
unit for voltage
volts
unit for time
seconds
unit for resistance
ohms
what are the three formulas used to find current?
charge/time, voltage/resistance, power/volts
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