Electricity In The Home Flashcards
What way does alternating current go (ac)
It alternates from left to right
When do we get AC
If we use an alternating potential difference (positive and negative)
What’s the uks main supply
AC 50hz and 240V
What are hertz (hz)
Amount of waves or frequency
What is potential difference
A measure of energy per unit of charge between 2 points in a circuit
What are all the equations for power
P=I^2(Current in A) x R (resistance in ohms)
P=I x V
P=V^2xR
What is power and its unit
The rate at which an appliance is supplied with or supplies useful energy
Power in watts (W)
What is charge
Positive or negative value carried by a particle
What’s the formula for charge
Q(charge in coulombs C) =I (current in Amps) x T(s)
What are resistors in a series
A series of resistors all with different values or the same in a circuit
How do u calculate resitance from resistors in a series
Rt= R1+R2+R3….
Rt=total resistance
What are resistors in parallel
Resistors on top of eachother
The resistance is always less than the smallest resistance in the system
How do you calculate resistors in parallel
R1xR2xR3…/R1+R2+R3…
What is direct current (DC)
Only flows one way
What’s resistance
A force that counteracts the flow of current
How is resistance calculated
R (in ohms) = v(volts)/I (current)
What’s ohms law and the equation to go with it
Electric current through a conductor (between 2 points) is directly proportional to the voltage (across the 2 points)
V(Voltage)= I(current) x R(ohms)
What are transformers
A system of 2 coils linked via an iron bar- it is able to step up or step down the voltage through electromagnetic induction
What’s electromagnetic induction
Creation of EMF by way of moving a magnetic field around a conductor.
What’s an Electromotive force and its formula
Electromotive force potential difference that tends to rise electric current
EMF= Wd(Work done in J) /Q (charge in coulombs C)
How do you calculate a transformer
N(Number of coils) s(secondary)/Np(primary)=V(voltage)s/vp
What are electrical costs
Electricity measured in Kw/h
Equation for electrical costs
Cost=Power(kw) x Time(hour) x Price per kw
What’s the difference between conductors and insulators in terms of free electrons
Conductors- many free electrons that move easily enabling current flow
Insulators - have few free electrons, restricting electrical flow
Equation for energy
E=P/T
How does short circuiting happen
When the current finds a way to bypass the appliance on a path that has little to no resistance
What happens when something short circuits
It can cause circuit damage or explosions
What colour and purpose does a live wire have
Brown (bRown to the Right)
Connects to fuse- dangerous wire-carries voltage
What colour and purpose does an earth wire have
Green and yellow
Connects charge and appliance to the earth so there is a low resistance way back down
What colour and purpose does a neutral wire have
bLue(to the Left)
Carries current in opposite direction
What happens when u switch a switch
The switch shuts the circuit so if it is live
What is a 2way switch
A switch that has 2 ways of getting turned off and on
