P2

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define current and state an equation that links current, charge and time, with units
electrical current is a flow of electrical charge (ampere) Q = IT Charge flow = Current X time
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what is meant by potential difference and and resistance in a circuit
potential difference (or voltage) is the driving force that pushes the change around, resistance is anything that slows the flow down (ohms)
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what is the equation that links potential difference, current and resistance
Potential difference (v) = current (A) X resistance (ohms)
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explain how you would investigate how the length of the wire affects its resistance
attach a croc clip at 0cm on wire, attach second one 10cm away, record the current and pd, record current, place another 10cm away, record new current, repeat for diff lengths of wire, calculate resistance with equation, longer wire greater resistanc
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name one linear component and one non linear component
a linear component have an I-V characteristics that's a straight line e.g a fixed resistor. non linear components have a curved I-V characteristics e.g filament lampoon a diode
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draw the I-V characteristic for an ohmic conductor, a filament lamp and a diode
in ur mind
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True or false? the resistance of and LDR increases with light intensity
light dependant resistor, in bright light resistance falls, darkness resistance is highest
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what happens to the resistance of a thermister as it gets hot
in hotness the resistance drops, in coolness the resistance increases
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true or false? potential difference in shared between the components in a resistace circuit
the potential difference is the same across all the components, identical bulbs connected in parallel will be at the same brightness
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how does the current through each component in a series circuit vary?
in series the same current flows through all components I1 = 12
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true or false? current is shared between the branches of a parallel circuit?
true, if two components are connected in parallel then the same current will flow through each component
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true or false? mains supply electricity in an alternating current?
true, it is ac ( the current is constantly changing direction)
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what is the potential difference and the frequency of the UK mains supply
230V and 50 cycles per second or 50 Hz
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name and give the colours of three wires in a three-core cable. why are they colour coded
The colour shows its purpose and easy to tell them apart. NEUTRAL WIRE: blue, completes circuit and carries current away, electricity in through live and out through neutral. 0V. LIVE WIRE: brown, provides alternating p.d, 230V. EARTH WIRE: green/yel
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explain why touching a live wire is dangerous
Can give you an electric shock, a large potential difference is produced across your body and current flows through you.
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describe the energy transfers that occur for a battery powered fan
energy is transferred electrically of a handheld fan to the kinetic energy store of the fans motor
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what is the power rating of an appliance
they're labelled with the max safe power that they can operate at. Tells you the max amount of energy transferred between stores per second when the appliance is in use.
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state three equations that can be used to calculate electrical power
Energy = power X time Power = potential difference X current Potential difference = Current2 X resistance
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what is the national grid
A giant system of cables and transformers that covers the UK and connects power stations to consumers. It transfers electrical power from power stations anyway on the grid
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explain why electricity is transferred by the national grid at a high pd but low current
you need one or the other. If you have a high current you lose loads of energy as wires heat and lost to surroundings. Much cheaper to boost the pd rly high, increasing pd decreases the current
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what are the functions of step down and step up transformers?
The pd is increased (stepped up) for efficient transmission, then brought down to safe, usable levels so reduced (stepped down) for domestic use
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Other cards in this set

Card 2

Front

what is meant by potential difference and and resistance in a circuit

Back

potential difference (or voltage) is the driving force that pushes the change around, resistance is anything that slows the flow down (ohms)

Card 3

Front

what is the equation that links potential difference, current and resistance

Back

Preview of the front of card 3

Card 4

Front

explain how you would investigate how the length of the wire affects its resistance

Back

Preview of the front of card 4

Card 5

Front

name one linear component and one non linear component

Back

Preview of the front of card 5
View more cards

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