Physics Paper 1 Electricity 9-1

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What is Current?
The flow of electrical charge.
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What do voltage and resistance do to current?
Voltage pushes the current around the circuit, Resistance slows the flow of current.
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What is the equation for charge with current?
Q (charge) = I (current) x t (time)
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What is the equation that links P.d, current and resistance?
Voltage = Current x Resistance
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At a constant tempature, the current flowing through an ohmic conductor is _____ __________ to the potential difference across it.
Directly proportional.
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What is a LDR dependent on? How does this effect the resistance?
Light intensity. Light - resistance decreases. Dark - resistance increases
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What is a thermistor dependent on? How does this effect the resistance?
Temperature. Hot - resistance decreases. Cool - resistance increases
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What is a sensing circuit?
Used to turn on or off components in a room depending on the conditions.
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In a series circuits, potential difference is ....
Shared between components
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In a series circuit, current is .....
The same in each component
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In a series circuit, the total resistance is ....
All the components resistance's added together
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In a parallel circuit, potential difference is ....
the same in each component
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In a parallel circuit, current is .....
Split between each component
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What is AC? Give an example.
Alternating current- Mains supply
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What is DC? Give an example.
Direct current- Battery supply
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What is the UK Mains supply voltage? What is the frequency?
230V, 50 Hz
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What three wires are in the plug?
Neutral Wire, Live wire and Earth wire
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What do each of the three wires in the plug do?
Neutral wire- Completes the circuit (current flows out using). Live wire- Provides the current from the mains supply. Earth wire- Doesn't carry current and prevents the casing from becoming live.
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What colour is each of the wires in the plug?
Neutral wire- Blue. Live wire- Brown. Earth wire - Green and Yellow.
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What equation links Energy transferred and Power?
E (Energy transferred) = P (Power) x T (Time)
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What equation links Energy transferred, charge and PD?
E (Energy transferred) = Q (Charge) x V (Pd)
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What equation links Power, voltage and current?
P (Power) = V (Voltage) x I (Current)
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What equation do you use if you dont know the PD and you are trying to calculate power?
P (Power) = I^2 (Current squared) x Resistance
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What is the National Grid?
A system of cables and transformers that cover the UK, connecting powering stations to consumers.
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What do electrical power stations need to assume throughout the day?
The amount of electricity usage/the demand for energy at a given time.
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Is the current high or low in the national grid?
Low
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Is the voltage high or low in the national grid?
High
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Why does the National grid use certain levels for voltage and current?
Its cheaper and prevents lots of energy loss
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What are the stages from the power station to the consumer by the national grid?
Power station - Step up transformer - Pylons - Step down transformer - Consumer
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What two types of materials are needed to rub together to create static build up?
Two insulating materials
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What happens when two materials are rubbed together?
Negatively charged electrons will move from one material to the other, creating two electrically charged materials. One positive, one negative.
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What effects the direction electrons move in static build up?
The type of material used
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What causes a spark?
Too much static - The electric charge builds up increasing the potential difference between the object and earth. Electrons then jump across causing a spark.
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What is an electric field?
A field created around any electrically charged object
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When you get closer to an electrically charged object, the _______ the field is
Stronger
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How do you show electric fields around an object?
Field lines- Straight lines coming out of an object, the arrow depending on the charge. Facing away if its positive, facing towards if negative.
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What happens when a charged object is placed in the electric field of another object?
It feels a force, attraction or repulsion.
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How do electric fields explain sparks?
Electric fields causes electrons in air particles to be removed (ionisation) which makes the air conductive.
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Other cards in this set

Card 2

Front

What do voltage and resistance do to current?

Back

Voltage pushes the current around the circuit, Resistance slows the flow of current.

Card 3

Front

What is the equation for charge with current?

Back

Preview of the front of card 3

Card 4

Front

What is the equation that links P.d, current and resistance?

Back

Preview of the front of card 4

Card 5

Front

At a constant tempature, the current flowing through an ohmic conductor is _____ __________ to the potential difference across it.

Back

Preview of the front of card 5
View more cards

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