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