P2- Electricity Flashcards
Define current
The flow of charged particles
The _ the resistance across a component, the _ the current that flows
Greater
Smaller
What is the equation for total charge
Charge flow = Current X time
What is the equation for potential difference
Potential difference=Current X resistance
What do ohmic conductors have
Constant resistance
What does LDR stand for
Light dependent resistor
What does the resistance of a thermistor depend on
Temperature
What happens to the resistance of a thermistor in different temperatures
Hot goes up cold goes down
How can you use LDRs and thermistors
in sensing circuits
How can sensing circuits be used
To turn on or increase the components depending on the conditions they are in
How are components arranged in a series circuit
Around in a line
What is the equation for total potential difference in a series circuit
Vtotal=V1+V2+…
What is the equation for current in a series circuit
I1=I2…..
What is the equation for total resistance in a series circuit
Rtotal=R1+R2
What is the equation for potential difference in a parallel circuit
V1=V2
What is the equation for current in a parallel circuit
Itotal=I1+I2+…
What does adding a resistor do to the total resistance in a parallel circuit
Reduces the total resistance
What type of supply is the mains supply
AC
What type of battery supply is used
DC
What does AC current do
Constantly change direction
What does DC current do
Constantly flow in the same direction
How many wires do most cables have
3
What are the 3 different wires in most cables
- Live wire
- Neutral wire
- Earth wire
What is the live wire
The wire provides the alternating potential difference from the main supply
What is the neutral wire
The neutral wire completes the circuit- when the appliance is operating normally, current flows through the live and neutral wires
What is the Earth wire
It’s protecting the wiring, and for safety - it stops the appliance casing from becoming live. It doesn’t usually carry a current- only when there is a fault
Can the live wire give you an electric shock
Yes
What is the equation for energy transferred
Energy transferred= Power(w) X Time(s)
What is the equation for energy transferred
E= Charge flow X potential difference
What is the equation for power including potential difference and current
P =VI
What is the equation for power including resistance and current ( this may be wrong)
P=I^2R
What is potential difference changed by
A Transformer
What does a build up of static electricity cause
Friction
When too much static electricity causes a spark what is there a lot of
Potential difference
Similar charges _ ,opposite charges _
Repel
Attract
What do electric charges create
Electric field
Where is an electric field created around
Electrically charged object
How can you show an electric field
Field lines
Charged objects in an electric field fell a _
Force
When are sparks caused
When there is a high enough potential difference between a charged object and the Earth
Define charge
Value of electricity flowing in a circut