5 - Electricity in the home Flashcards
Batteries run on…
direct current.
Mains electricity runs on…
alternating current as it repeatedly reverses its direction in successive cycles, constantly changing the polarity of potential difference.
The neutral wire is earthed at…
the local electricity substation.
Live wire potential in the UK is…
+/- 325V
Typical power stations generate electricity at an alternating p.d. of…
25000V
Step transformers increase…
p.d. in order to decrease the current so less energy is lost.
Step down transformers decrease…
p.d. to match the potential of household appliances.
Earth wires at connected to the ground at a potential difference of…
0V and only carry current if there is a fault.
Why are pins made of brass?
- Good conductors
- Harder than copper
- Don’t rust/oxidise
Cables are made of…
three copper wires surrounded by rubber or flexible plastic material.
A short circuit is…
a very big current that passes when a live wire directly touches the neutral
How is energy transferred through a resistor?
When a resistor is connected to a battery, work is done by the battery to make electrons pass through. The electrons collide with vibrating metal ions of the resistor, transferring kinetic energy which increases the temp. of the resistor.
