# Physics - P3

when an object gains electrons, what is it's charge?
negative
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when an object loses electrons, what is it's charge?
positive
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how is static caused?
transfer of electrons
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when will two objects attract?
when their charges are opposite
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how can you test if an object is charged?
hold it near small pieces of paper. they will jump if the object is charged, as it induces a charge in the paper. you can also hold it near a stream of water - it will bend if a charge is present.
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when will an object become neutrally charged?
when there is an equal amount of positive and negative charge in an object.
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if the materials involved in an experiment are conductors, what will happen in terms of electrons?
electrons will flow back into or out of them, meaning they stay neutral.
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if the materials involved in an experiment are insulators, what will happen in terms of electrons?
electrons cannot flow, so a positive static charge is left on the object that has lost electrons, and a negative charge on the object that has gained electrons
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define potential difference.
driving force that pushes current around
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define current
rate of flow of electric charge. current will only flow through a component if there is a pd, and the circuit is closed.
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equation for charge
current x time
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equation for energy transferred
charge x pd
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what components does a standard test circuit have?
voltmeter, ammeter, cell, variable resistor, thermistor.
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equation for potential difference
current x resistance
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what is the structure for a series circuit?
all components are connected in a line, meaning removing one component will affect the circuit greatly.
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what is the structure for a parallel circuit?
each component is seperately connected to terminals, meaning removing a component won't have much affect on the circuit.
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what is the rule for pd in a series / parallel circuit?
series = shared across brances parallel = same across branches
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what is the rule for current in a series / parallel circuit?
series = same across branches parallel = shared across branches
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what is the rule for resistance in a series / parallel circuit?
series = total is sum of resistance across each branch parallel = always smaller than that of the branch with the smallest resistance
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equation for power (1)
potential difference x current
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equation for power (2)
current^2 x resistance
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define magnetic flux density
strength of magnetic field
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how can you see magnetic field patterns?
use iron filings on top of paper, or a compass to mark out direction.
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the larger the electric current...
...the stronger the magnetic field
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how can you increase current with a solenoid around an iron bar?
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equation for a force on a conductor carrying a current
magnetic flux density x current x length
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what does each finger represent in Fleming's left hand rule?
thuMb = Motion, First Finger = Field, seCond finger = Current
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how does a motor work?
a current carrying coil sits between two opposite poles of a magnet. since the current flows in different directions, each side experiences forces in the opposite direction.
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## Other cards in this set

### Card 2

#### Front

when an object loses electrons, what is it's charge?

positive

### Card 3

#### Front

how is static caused?

### Card 4

#### Front

when will two objects attract?

### Card 5

#### Front

how can you test if an object is charged?