Electricity and Magnetism Flashcards
define and give examples of static electricity
static electricity is the build-up of electrons in one place e.g. lightning, rubbing a balloon against your hair
define current electricity
electric current is the flow of electrons
what and why is the relation of the flow of conventional current and the flow of electrons
opposite
conventional current goes positive to negative and electrons go negative to positive
distinguish between an electrical conductor and an insulator
*Components that allow electricity to flow through easily are good conductors
*Components that make it hard for current to flow are good insulators
compare a series circuit with a parallel circuit
*in a series circuit, there is only one path for the electricity to travel as it has no branches or junctions and components are one after the other. Every component has to work or else no components will work
*in a parallel circuit, there are two or more individual circuits connected to the same power supply, each branch takes its own supply of current from the cell/battery
define voltage
The potential difference in a circuit
what unit do you measure voltage in
volts
define current
the flow of electrical charge in a circuit
what unit do you measure current in
amps
how do you correctly set up and record the current and voltage in a parallel circuit
*ammeter - at the back of all the branches and before the current goes into any branch
*voltmeter - before and after each component
how do you correctly set up and record the current and voltage in a series circuit
*ammeter - goes anywhere
*voltmeter - the wires go before and after every component
define resistance
how much opposition there is to a current
what units do you measure resistance in
ohms (Ω)
what is the relation of resistance between conductors and insulators and why
*conductors have low
*insulators have high
*conductors allow the electricity to flow through it & insulators don’t
what is an LDR
*a component with a resistance that depends on light intensity - used to detect light levels
how does an LDR work in a circuit in both low and strong light
*they have low resistance in strong light
*they have high resistance in the dark
what and why takes the easiest route
charge as it wants to get round the circuit as quickly as possible and will do it in the quickest way possible
what does a diode do
*only allows electricity to pass through it in one direction
explain what an LED is and how it works
*a diode that emits light when a small current flows through it
*it only allows light to flow through it in one direction
what is the role of switches
to control when current goes through a circuit
switch
open - two lines leading up to two different dots and a line from one of the dot is going above the other dot
closed - two lines leading up to two different dots and there is a line connecting them together
cell
two lines leading up to two different lines and one line is bigger than the other
battery
two cells and a dotted line going from a short line to a long line
diode
a side on triangle with a line going through it inside a circle
