P2: electricity Flashcards
Define electricity
The motion of charged particles
How does an object become charged?
For something to become charged it has to gain or loose electrons
Why do charge objects attract or repel?
Charged objects attract or repel because they create electric fields around themselves
How is lightning made?(4):
- clouds become negatively charged due to friction from hail.
- this repels electrons on the ground, revealing the protons
- electrons try to move to the ground, those who have create a path for other electrons
- this creates heat and light,which is lightning
What fuels a circuit?
The fuel in a circuit is the battery/cell , the ENERGY it provides is measured in JOULES
charge(3):
Measured in coulombs (c)
Charge= current(a) x time(s)
(Q=I X T )
Define potential difference
The energy transferred per unit charge
PD= energy(j)/charge(c)
Define current
The speed at which they move around, measured in AMPS (A)
Define resistance(2):
- The measure of how much the current is slowed down by components in a circuit
- Resistance(Ω)= current (a) / potential difference (v)
Electricity is …
Always trying to find the fastest route to the ground
What is ohms law?
Ohm’s law states that the current through a conductor is directly proportional to the voltage across two points.
Overhead and under ground cables(6):
Overhead: \+ easier to fix + does not require a cooling system + could fall - ugly Underground : \+ electricity won’t shock anyone - requires cooling system (expensive)
Series circuits(2):
- CURRENT IS THE SAME
- POTENTIAL DIFFERENCE IS SHARED
Parallel circuits(2):
- CURRENT IS SHARED
- POTENTIAL DIFFERENCE IS THE SAME
What is the purpose of the fuse?
If for any reason the voltage gets too high the thin wire in the fuse will snap and melt, cutting the circuit
What is the mains electricity?
230V
What is the equation of power?
Power= voltage x current P= V X I
Power= (current)^2 x resistance P= I ^2 x R
Power = Work done / time P= W/t
The national grid(5):
Power station-step up transformer-pylons and cables-step down transformer-house
Power:
P= energy(j)/time(s)
Direct current:
Flow of electric charge in only one direction
Alternating current:
Electric current continually changes direction
Live wire(2):
- Brown
- Conducting wire connection that carries the alternating current
Neutral wire(3):
- Blue
- Conducting wire connection that allows electrical charge to its return source
- Completes the circuit
The National Grid (definition):
A network of cables and transformers that links power stations to consumers across the country
