Electricity in real life (home, national grid ect) Flashcards
What is alternating current
The current is constantly changing direction and is produced when the voltage is alternating
What is direct current
Current that always flows in the same direction
What is the potential difference in the ac supply in a home
230V
What is the frequency of the mains supply
50hz
What is the live wire
Brown
Provides the alternating potential difference (230 V) from the mains supply
What is the neutral wire
Blue
Completes the circuit and carries away the current
It is usually 0 V
What is the earth wire
Green and yellow
Only carries the current when there is a fault and stops the appliance from becoming live
What happens if you touch a live wire
Electric shock
the difference in the potential difference causes the current to flow through you
How do kettles work
Kettles transfer energy electrically from the mains AC supply yo the thermal energy store of the heating elements inside the kettle
How do hand held fans work
Energy is transferred electrically from the battery of a handheld fan to the kinetic energy store of the fans motor
What does a higher current mean
More energy transferred to the thermal energy store and reducing the efficiency
What is a power rating
The maximum amount of energy transferred between stores per second when the appliance is in use
What does a lower power rating mean
Cheaper to run as less electricity is required
What happens when there is a lower potential difference
The charge gives up energy
What is the national grid
Web of wires that covers the whole of Britain that gets energy from power stations to consumers
What causes increases in energy demands
Getting up in mornings
Coming home from school/work
When it is colder/darker
Popular sporting events
How does the national grid transfer energy
By using a high potential difference (400,000 V) and a low current to reduce thermal energy loss (more efficient)
How is potential difference increased in the national grid
Step up transformers
How is potential difference decreased in the national grid
Step down transformers
