circuits SCIENCE

Where does the electric current flow from

the electric current flows from the negative end of the cell to the positive end

What is the convential current

drawing arrows as if the current flowed from positive to negative

What are series circuits

A circuit with only one path for the current to take

what is an electric current

the flow of electric charge round a circuit

what is the units for current

amps

How can we measure current

with an ammeter

What is current like in a series circuit

The same all the way round the circuit

what is current like in parralel circuits

The current in the branches adds up to the current leaving the cell. (e.g 3 at top 1 on one branch 2 on the other branch)

What is the energy conversions in a circuit

The cells chemical energy that gets transferred to electrical energy which is carried by the electrons when the electrons pass through components the energy is then transferred to other forms of energy(e.g thermal and light for a bulb)

Is potential difference the same as voltage

YES

What does potential difference tell us

A potential difference of 1 volt tells us that 1 joule of energy is transferred for each coulomb of charge that is moving through the circuit

How do you measure the potential difference of a component

What is potential difference like in series circuits

The total voltage across all the components is the same as the potential difference across the cell

What is potential difference like in parralell circuits

potential difference is the same across each component

what is potential difference across a cell like when it goes from 1 cell to 2

voltage doubles

What is a battery

two or more cells connected together

what is charge measure in

Coulombs (C)

How do you work out the charge flow

charge flow = current x time

What is the formula to work out energy transferred

energy transferred = charge flow x potential difference

What is energy transferred measure in

Joules (J)

What does resistance tell us

The potential difference required to drive a current through a component

What unit is resistance measured in?

Ohms (Ω)

What is the formula for resistance

resistance = voltage/current

How is electrical energy transferred to other forms of energy

As the elctrons move through a conductor they collide with the atoms in it transferring the energy

What is current through a resistor directly proportional to

Current through a resistor is directly proportional to voltage e.g (current 0.1 voltage 1 current 0.2 voltage is 2)

What does this show

That resistance is constant and does not change if current is increased

When will the resistance not stay constant

when the temperature isnt constant

What are resistors in series like

resistors in series add together (e.g one resitor has 50ohms and one has 100 the resistance is 150 ohms)

What are resistors in parrelell like

the total resistance of two resistors in parrellel is less than the resistance of the smallest individual resistor

what is an ionised cell

a cell where an electron has got enough energy to leave the rings. Causes a positive charge