Chapter 11 - Electricity in the home Flashcards
Whats the equation for voltage ?
voltage = energy transferred / charge
Whats the equation for energy transferred ?
energy transferred = voltage x current x time
Whats the equation for electrical power ?
EP = voltage x current
What are the ‘units’ of electricity ?
kilowatt hours (kWh)
What does 1 kWh represent ?
1000 W of electricity is delivered for 1 hour
Draw a 2 way switch and check with page 160
Can be a 6 mark Q
What is the wire with the blue insulation ?
The neutral wire
What is the wire with the brown insulation ?
The live wire
What is the wire with the yellow and green insulation ?
The earth wire
What is a fuse ?
A safety device consisting of a short length of fine wire which melts if too much current flows through it, thus breaking the electrical circuit.
How do you choose a fuse for an appliance ?
- find out how much current should flow through it
- select a fuse with a rating only slightly higher than the normal current
e.g 1.5 A ==== 3A fuse not a 13A (too much current)
Whats the purpose of the earth wire ?
If electricity flows through the object the earth wire will carry it away instead of into the person using the object.
What does double insulated mean and draw its symbol ?
The appliance is fitted with an outer plastic case, so no electricity will conduct through it and harm the user. They may only contain a live and neutral wire.
What is the purpose of the live wire ?
A wire in an AC system where the voltage can be dangerously high.
Why is the fuse placed on the live wire side of the circuit ?
The fuse will melt and the live wire will disconnect. Making it much safer fir the user.
