P2 Current Elctricity

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  • Created by: KAustria
  • Created on: 17-05-14 14:47
What happens when two insulating mateirals are rubbed together?
electrons are rubbed off one material and deposited on the other.
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What charge is an object if it gains electrons?
Negative
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What charge is an object is it looses electrons?
Positive
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By rubbing insulating materials together, what is the process called?
Charging by friction
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What will happen if two negatively charged objects are brought closer together?
They will repel as they have the same charges
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When polythene in rubbed with a cloth, what happens?
Electrons move from the cloth to the rod and so the polythene rod is negatively charged
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When acetate is rubbed with a cloth, what happens?
Electrons move from the acetate to the cloth and therefore the acetate rod is positively charged
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What does a light-emitting diode do?
Emits light when a current passes through it
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What does a diode do?
Allows electricity to flow in one direction
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What does an Ammeter do? and how should they be connected?
Ammeters measure electric current and should be connected in series ot the component.
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What does a resistor do?
Limits the amount of current in a circuit.
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What does a voltmeter do ad how should it connected in a circuit?
Voltmeters are used to measure the potential difference. They should be connected parallel to the component.
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What is resistance?
The opposition to current flow and is measured in the units ohms.
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What is Ohm's law?
The current through a resistor at a constant temperature is directly proportional to the potential difference across the resistor.
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Components that obey hm's law are known as what?
ohmic components
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Describe the current - pd graph for a filament bulb
1. The line is a curve 2. Current is not directly proportional to the pd 3. Temperature increases as the resistance increases due to the incease flow of current.
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What happens to the line of a diode in a current-pd graph when the direction of current is reversed?
The line remains on 0 because current through a diode only flows through one direction
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What happens to the resistance of a light -dependant resistor as the light falling on it gets brighter?
It decreases
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What happens to the resistance of a thermistor as temperature increases?
Resistance decreases
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What effetc does reversing the pd across a fiament bulb have on the current - pd curve?
No diffference
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What are the main features of a series circuit?
1. Components are connected to one after another 2. If a break occurs, charge will stop flowing through the circuit.
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What are the 2 variables that current depends on?
1. The potential difference of the supply 2. The total resistance
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How could you find the pd supply in a series circuit?
By adding all of the pd across individual components.
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How does an increase in the resistance of a component effect the supply of pd in a series circuit?
Bigger share
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What are the features of a parallel circuit?
1. Components are connected across the supply 2. IF there was a break, charge can still flow through other parts.
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What is the pd like of a components in a parallel circuit?
They are all the same
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Why can different amounts of current flow through different components in a parallel ciruit?
There are junctions in the circuit
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What are 3 main points you need to remember with components in a series?
1 The current is the same in each component 2. Adding the pd gives the total pd 3. Adding the resistances gives the total resistance
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What are 2 main points you need to remember with components
1. The total current is the sum of current flowing through the separate components 2. The bigger the resistance the smaller the current.
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Other cards in this set

Card 2

Front

What charge is an object if it gains electrons?

Back

Negative

Card 3

Front

What charge is an object is it looses electrons?

Back

Preview of the front of card 3

Card 4

Front

By rubbing insulating materials together, what is the process called?

Back

Preview of the front of card 4

Card 5

Front

What will happen if two negatively charged objects are brought closer together?

Back

Preview of the front of card 5
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