physics tets 3
V
Voltage
Voltage flows _____________ a circuit.
across
Predict how the brightness of bulb A changes when the switch is opened. Explain.
does not change because current in A does not change.
breaking stack magnets in half does what
each time is broken, new south and north poles established
how does adding a single bulb in series with another bulb or network affect the resistance of the circuit?
increases it more bulbs= more resistance
conductive metals (make) lights what
lighter
total resistance in paralell
product/sum
bar magnet broken in half does what
2 new magnets, each is half as strong as before
particle moving parallel mag
If the particle is moving parallel to the field it experiences no force,
How does the amount of current through a battery connected to a single bulb compare to the current through a battery connected to a two-bulb parallel circuit? Explain, based on your observations.
More resistors (bulbs) = more current The current through the two-bulb parallel circuit is twice the current through a single bulb circuit.
What can you infer about the total resistance of a circuit as the number of parallel branches is increased or decreased?
Resistance for n parallel resistances will be R/n. n= bulbs
Bulbs in Parallel
Resistance- decreased, flow if charge- increased - two paths for charge to flow through
Predict the relative brightness of the bulbs in the circuit with the switch closed. Explain.
Switch closed is equivalent to B & C in parallel with the combined resistance RBC in series with A. RA = 1R; RBC = R/2. Total resistance = 1.5R. All current will flow through A, then split between B and C. B and C will have half the current and one-quarter (P=I2R) the power of A. A will be twice as bright as B or C. Because A divides equally to B and C
Is the brightness of each bulb in the two-bulb parallel circuit greater than, less than, or equal to that of a bulb in a single-bulb circuit?
The brightness (current, power) is the same.
how does the current through the battery seem to divide and recombine at the junctions of the two parallel branches
The current through the battery must be the sum of the currents through the bulbs.
series circuit current and voltage
always equal
class 2
attracted to but not eachother
Class 1 magnetic
attracted to each other permanent magnets
requirements for bulb to light circuit
complete loop that is closed different sign battery ends connected to eachother
how does adding a single bulb in parallel with another bulb or network affect the resistance of the circuit?
decreases current
a pair of resistors in parallel
eq resistance= product/sum
How does the magnetic field of the stack of magnets compare to the magnetic field of the bar magnet?
equal
Two- Bulb Parallel- amount of current through each bulb
equal current
how does the current through the battery in a single-bulb compared to the current through the battery in a two-bulb series circuit
f light bulbs are connected in series to a voltage source, the brightness of the individual bulbs diminishes as more and more bulbs are added to the "chain". The current decreases as the overall resistance increases. Decrease in size fo current each time more bulbs are added to the chain
Bar magnet compass points
farther in distance, weaker interaction
current in the lamps through
flows through first lamp and then second
A student has briefly connected a wire across the terminals of a battery until the wire feels warm. The student fins the wire seems to be equally warm at points 1,2,3,
heat friction from electrons v=IR all apart of a series
sum of currents
in two branch paths equals the current before it divides
Adding more bulbs in series cause the total resistance to
increase
particle moving right angle mag
it experiences the biggest force when it moves at right angles to the field.
class 3
neutral
parallel circuit current and voltage
not always equal
when an uncharged pith ball is brought near one of the poles of the magnet
nothing happens
poles
parts of a magnet where the magnetic effects are the strongest
I is
resistor
The circuit at right contains three identical bulbs and a battery. You may use 2 batteries in series to make a higher voltage. Connect and disconnect a wire to act as a switch
setup
How does current through a bulb in a single circuit compare with the current through the same bulb when it is connected in series with a second bulb
the single bulb is brighter because it has more current. With the second bulb it has less current as it divided equally between the two bulbs.
current flows
through a circuit
Bulbs in Series
two-bulb circuit with identical bulbs connected one after the other
Ohm's Law- current through a battery would change
v=ir I=V/R -since Voltage is the same (Same battery), then resistance is twice as much as 1/2 of I
R
Current
