Physics ( Electricity) Flashcards
What’s alternating potential difference
When the potential difference changes direction
Why does the national grid use step-up transformers
Step up = increases the potential difference
= decrease the current
= stops cables from overheating like a high current would, which would mean lots of lost energy
Why does he national grid use step down transformers
To reduce the potential difference and increase the current. This makes it safer for the consumer
What are the three wires in a cable
Neutral wire
Live wire
Earth wire
What does the earth wire do
Stops the appliances casing from becoming live
What does the live wire do
Provides the alternating potential difference
What does the neutral wire do
Carries the current away
Electricity usually travels in the live wire and out through the neutral wire
What’s the equation for potential difference
V=ir. ( vir )
Potential difference = current x resistance
