P5 - Electricity In The Home 1️⃣✅ Flashcards
What is the equation that links charge, current & time?
Q = I x t
What is the equation that links energy, charge & voltage?
E = Q x V
What is the equation that links potential difference, current & resistance?
V = I x R
What is the equation that power, current & resistance?
P = I(squared) x R
What is the equation that links power, energy & time?
E = P x t or P = E/t
What is the equation that links power, current & voltage?
P = I x V
Why is double insulation needed?
If the live wire were to become loose and touch the metal case of the object, there would be another layer or material to prevent the next person using the appliance from getting electrocuted.
What is meant by the term double insulation?
When something is double insulated it is coated in a material that is a poor conductor of electricity (plastic) to that if the live wire were to touch the metal casing of a appliance there would be another layer of insulation to prevent the next person to use it from getting an electric shock.
What is the point of having an earth wire on certain appliances?
If the live wire were to be loose it allows for the current passing through a case of an appliance to pass down a low resistance copper wire rather than a person.
What is it called when an appliance has an earth wire?
The appliance would be earthed.
What colour is the neutral wire?
Blue
What colour is the live wire?
Brown
What colour is the earth wire?
Yellow/green
What does the symbol Q represent and what are it’s units?
Charge, coulombs
What does the symbol I represent and what are it’s units?
Current, amps
What does the symbol t represent and what are it’s units?
Time, seconds
What does the symbol V represent and what are it’s units?
Potential Difference/Voltage, volts
What does the symbol R represent and what are it’s units?
Resistance, ohms
What does the symbol E represent and what are it’s units?
Energy, joules
What is frequency?
The number of waves per second
What are the units of frequency?
Hertz
What is mains electricity?
The electricity supplied to our homes
What is the frequency and volts for the mains supply in the UK?
230 volts and 50Hz
What is the symbol for Hertz?
Hz
What colour is the live wire and where is it located?
Brown & its located on the right of the plug
What colour is the earth wire and where is it located?
Yellow/green & its located at the top of the plug
What colour is the neutral wire and where is it located?
Blue & its located on the bottom left of the plug
How many volts are in the live wire?
230V
What material are the pins of the plug made of and why?
Brass because its durable and a good conductor
What material is the casing of the plug made of and why?
Hard plastic because its a good electrical insulator and wont break easily to prevent damage
What material is the casing of the cable made of and why?
Rubber because its a good electrical insulator and its flexable
What material is the wire made of and why?
Copper because it has a very high conductivity / very good electrical conductor
What is the national grid?
The National Grid distributes electricity across the country.
What is the function of the neutral wire?
The neutral wire and completes the circuit from the appliance back to the supply
What is the function of the live wire?
The live wire carries the voltage
What is alternating current? a.c
Electric current in a circuit that repeatedly changes direction from + to -
What is direct current? d.c
Electric current in a circuit that is only one direction e.g + or -
What is an oscilloscope?
A device used to display the shape of an electrical wave
What is amplitude?
The distance from the peak of the wave to the line in the centre
What is the time period?
The distance between waves
What is static electricity?
The build up fo charge on insulating materials
Why are all materials usually neutrally charged?
Because their postive protons and negative electrons cancell eachother out
What happends when you rub two objects together?
The friction between the two objects causes electrons to be rubbed off one of them and onto the other one
What happens when you rub two conducting mateirals together?
Because electrons can move freely in a metal once transferred they would just flow straight back again so no charge ever builds up
What happens when you rub two insulating mateirals together?
e.g. rod and cloth
When you rub two insulating materials together the negative electerons would transfer and would remain due to them not being able to flow.
What charge would be left on the insulating material that was rubbed onto the other
e.g cloth
It would be left with a positive static charge due to the loss of electrons
What charge would be left on the insulating material that was rubbed on by another material
e.g. rod
It would be left with a negative static charge due to the gain of electrons
What type of subatomic particle are being transferred when 2 objects are rubbed together?
Negative electrons only
What is a surge?
A sudden increase in current
What do fuses/ circuit breakers do?
Break the circuit when the current gets too high
What is a fuse/ how does it work?
A very thin piece of wire that is connected to the live wire that will heat up very quickly when current is too high (a surge) and will cosequently melt, therefore breaking the circuit meaning no more current can flow through it
What are the pros & cons to fuses?
- Simple & cheap
- Permanently broken after a single surge/ use so have to be replaced
What are the pros/ cons to a circuit breaker?
- More expensive
- Can be reset after being tripped so dont need to be replaced
