Electricity Flashcards
Electric current
The electric current is the flow of electric charge around a circuit (Amps)
It moves from the negative end of the cell to the positive end of the cell
Series circuit
It has no branches. The current can only flow in one path
Measuring current
We can measure the current in a circuit by using an ammeter
Is current used up in a circuit
Current is never used up in a circuit
Is the current the same or different all the way round the circuit
In a series circuit, the current is the same all the way round the circuit
Conventional energy
Scientists always draw the current in the opposite direction
Branches
A parallel circuit contains branches
Current in a parallel circuit
The current in the branches add up to the total current leaving the cell
Coulombs (C)
Electrical charge is measured in C
A current of 1 ampere = 1 coulomb of a charge flowing per second
Name 1 thing that stores chemical energy
Battery
Potential difference
P.D of 1V tells us that 1J of energy is transferred for each coulomb of charge that is moving through the circuit
P.D in a series circuit
P.D is split between components
P.D in parallel circuit
For components connected in parallel, the p.d across each component is the same
P.d between batteries
2 cells = 1 battery
E.g. 1 cell = 6V
1 battery = 12 V
What is a flow of electrons
Electric current
What is the current through a resistor
Directly proportional to the potential difference
Ohmic conductor
In dark conditions what is the resistance of an LDR (light dependant resistor)
High resistance
In the light what is the resistance of the LDR
Very low resistance
How much energy does a circuit need to pass through the LDR
Very little energy
Thermistor
The resistance of a thermistor decreases if the temp increases
In cool conditions what is the resistance of the thermistor
High resistance
How much energy does the current need to pass through the thermistor
Lot of energy
What is the p.d across the thermistor
High
What is D.C (direct current)
The current from a cell is a d.c
What is a A.c (alternating current)
Mains power electricity in the UK is an alternating current
The current is constantly changing direction
Brown wire
Live wire
Carries the alternating potential difference from the supply
What is the live wire connected to
To the fuse
Blue wire
Neutral wire
Completes the circuit
P.d=0v compared to the live wire
Green/ yellow stripped wire
Earth wire
Safety wire to stop the alliance from becoming live
Is the live wire dangerous
Extremely dangerous and could easily be fatal if touched
They could be electrocuted
What does National grid consist of
Transformers
High voltage cables
What happened when electricity passes through step up transformer
Increase pd
Reduces energy lost in the transmission cables
What happens to the energy in the power cables when the pd is very high
Less energy is lost
What happens when electricity pass through step down transformer
Reduces pd
Electric current
The electric current is the flow of electric charge around a circuit (Amps)
It moves from the negative end of the cell to the positive end of the cell
Measuring current
We can measure the current in a circuit by using an ammeter
Is current used up in a circuit
Current is never used up in a circuit
Is the current the same or different all the way round the circuit
In a series circuit, the current is the same all the way round the circuit
Current in a parallel circuit
The current in the branches add up to the total current leaving the cell
Potential difference
P.D of 1V tells us that 1J of energy is transferred for each coulomb of charge that is moving through the circuit
P.d between batteries
2 cells = 1 battery
E.g. 1 cell = 6V
1 battery = 12 V
What is a flow of electrons
Electric current
What is the current through a resistor
Directly proportional to the potential difference
Ohmic conductor
In dark conditions what is the resistance of an LDR (light dependant resistor)
High resistance
In the light what is the resistance of the LDR
Very low resistance
How much energy does a circuit need to pass through the LDR
Very little energy
Thermistor
The resistance of a thermistor decreases if the temp increases
In cool conditions what is the resistance of the thermistor
High resistance
How much energy does the current need to pass through the thermistor
Lot of energy
What is the p.d across the thermistor
High
What is Power
Power is the rate at which energy is transferred
Is the live wire dangerous
Extremely dangerous and could easily be fatal if touched
They could be electrocuted
What happened when electricity passes through step up transformer
Increase pd
Reduces energy lost in the transmission cables
What happens to the energy in the power cables when the pd is very high
Less energy is lost
What happens when electricity pass through step down transformer
Reduces pd
