P4-Electricity Flashcards
There are the same number of what as protons in an atom?
Electrons
What do you call a charged atom?
An ion
Do like charged repel or attract?
Repel
Describe what happens when 2 insulating materials are rubbed together?
Some electrons would be rubbed off one insulator on to the other through friction.
What is transfered when objects become charged?
Electrons
What kind of force acts between charges
A non contact force.
What does a cell do ?
It provided the circuit with a source of potential difference
What does a resistor do?
It limits the flow of current
What does a thermistor do?
As the temperature increases the resistance decreases and vice versa.
What is a LDR?
It is like a thermistor but with light.
What does a diode do?
It allows current to flow in one direction only.
What does a fuse do?
It explodes when a current above a certain number passes through
What does a voltmeter measure?
The potential difference.
What does an ammeter measure?
The current
An electric current is the flow of what?
Electrons
Why are metals good conductors of electricity?
As the electrons are free to move between the atoms.
What is the equation for charge?
Charge(Q)= current(I) x time(T)
What is charge measured in?
Coulombs
What is current measured in?
Amps
What is time measured in?
Seconds
What is the equation for energy transfered?
Energy transfered (E)= Charge (Q) x potential difference (V)
What is potential differences measured in?
Volts
What is energy transfered measured in?
Joules
What is Ohm’s law?
Potential difference(V) = Current(I) x Resistance(R)
What is resistance measured in?
Ohms
What does directly proportional mean?
When a graph is a straight line through the origin.
What is current?
The flow of charged particles.
What does the current do in parallel and series’s circuits?
In a series circuit all the components have the same amount of current flowing through them and in a parallel the current splits between the branches.
What does the voltage do in a series and parallel circuit?
In a series circuit the voltage splits between the components but in a parallel it stays the same.
How does resistance work in a series circuit?
The resistance of the components is added together, so more resistors means more resistance.
How does resistance work in a parallel circuit?
The resistance splits between the branches , so more resistors means an overall decrease in resistance. this is as when you add another loop it gives the electrons more options and therefore decreases the resistance
What direction does current flow?
Clockwise - from the positive terminal to the negative terminal.
What is the current?
The current is the rate at which the electrons flow past a point in a circuit
