Physics: Electricity Flashcards
What is Current
Flow of electrical charge
What is current measured in
Ampere A
What is Potential Difference
Driving force that pushes the charge round
What is Potential Difference measured in
Volt V
What is Resistance
Electrical force that slows down the flow
what is resistance measured in
Ohms (Omega symbol)
What does Q=IT mean
Charge flow (coulombs C) = Current (A) x time (s)
What is the potential difference formula
Potential Difference (V) = Current (I) x Resistance (R)
What is the Potential difference in a Series Circuit
Potential Difference is shared so Vt = V1 + V2 + ….
What is the Current in a Series Circuit
Current is the same everywhere so I1 = I2 = ….
What is the Resistance in a series Circuit
Resistnace adds up Rt = R1 + R2
What is the Potential difference in a Parallel Circuit
Potential Difference is the same everywhere so V1 = V2 = ….
What is the Current in a Parallel Circuit
Current is shared between branches It = I1 + I2 + ….
What three wires are in a plug
Live Wire, Neutral Wire, Earth Wire
Describe the Live Wire
Brown wire that provides the alternating potential difference (230V) from the mains supply
Describe the Neutral Wire
Blue wire that completes the circuit and carries current away
Describe the Earth Wire
Green and Yellow that is used for safety. It only carries current when there is a fault
What are the energy transferred formulaes
E = Pt Energy transferred = Power x time or
Energy transferred = Charge flow x Potential difference E = QV
What are the two Power equations
P = VI Power = Potential difference x Current or P = I2R Power = Current squared x Resistance
What is the voltage of the National Grid
230V
What is the frequency of the National grid
50Hz
What is Static electricity
The charges are not free to move which causes them to build up and spark
What causes Static electricity
Friction
What happens to positive charges and electrons in static electricity
The positive charges never move only the electrons
What do two objects with opposite electric charges do
repel each other
What do two objects with same electric charges do
attract each other
How do sparks happen
Caused when there is a high enough potential difference between a charged object and an earthed object
