P3- Electricty Flashcards
define static electricty
The build up of charge in insulating materials
what happens when static electricty is dischared
sparks are produced
Do all objects have charge?
Yes but most object cancel out as they have an even amount of negitve and positve cancel each other out
What happnes when two insulating objects are rubbed together
The friction causes electrons to be rubbed off onto the other one
What happnens when two conducting materials are rubbed together
The charge lost travels back into the orginal object
can static electricity be built up in conducting materials
No it cant
What sub atomic particles are transfered when friction is created
Only electrons are transfered
What happens when the negtive charge builds up on an insultating object
A potenial difference is created between the negtively cahrged obejct and the earth (or any other earthed object)
What is the charge of an earthed object
0Volts
What happens when the potential difference between an earthed object and an insulator becomes large
Electrons ‘jump’ between the gap which create sparks
Can charge build up on conducting materials
Sometimes- although it is uncomen
What is an example of charge building up on a conducting material
A car creating friction between the wind as it drives
Do all charged obeject have an electrical field
Yes
Which way do elecrical field lines point
Positve to negitive
(positive point outwards, negitive point inwards)
How must electrical field lines be drawn
At a right angle to the surface
Where is a electrical field strongest
Clostest to the object
Where is the electrical field weaker
furhter away from the object
What happens when charged particles become closer
electrical fields
There electrical fields become stonger
What is the name of the force that attracts two particles together
Electrostatic force (or attraction)
Is air an insulator or a conductor
Its an electriacal insulator
What happens when air comes into contact with a strongly charged object
The air ionises(loses electrons) which causes the air to become a conductor and allows electrons to travel through as sparks
Define Coulomb
The unit of charge.
Diode
A component that only allows current to flow through in the forward direction. They
have very large resistances in the reverse direction.
Electric Current
The rate of flow of electrical charge. Its value is the same at any position in
a single closed loop. In metals, the charges that flow are electrons.
Filament Lamp
A light emitting component consisting of an enclosed metal filament. Its
resistance increases as the filament’s temperature increases.
Light Dependent Resistor (LDR)
A light sensitive component whose resistance decreases
as its temperature increases.
Light Emitting Diode
A device that gives out light when a current flows through it. Current
can only flow through it in one direction, and a minimum voltage must be applied across it
before it illuminates.
Ohms
The unit of resistance.
Ohm’s Law
The current flowing through an Ohmic conductor at constant temperature is
directly proportional to the potential difference across it.
Potential Difference
The energy that is transferred per unit charge between two points in a
circuit. It is often also called a voltage.
Power
The rate at which an appliance transfers energy. For a circuit component, it is equal
to the product of the current passing through it and the potential difference across it.
Resistors in Parallel
The total resistance is less than the lowest individual resistance.
Resistors in Series
The total resistance is equal to the sum of the resistances of the individual resistors.
Series circit
Components connected in series have the same current passing through each
component but share the total potential difference of the power supply.
Thermistor
A temperature dependent component, whose resistance increases as its
temperature decreases
Volt
The unit of potential difference. One volt is equal to one joule per coulomb.
Watt
The unit of power.
