current, potential difference and resistance

• current is...


  a flow of electric charge
• what is current measured in?

  amperes (A) using an ammeter connected in series
• current in a series circuit is...


  the same everywhere
• current in a parallel circuit is...

  shared between branches
• current flowing through a component depends on...

  the potential difference across it and the resistance of the component
• current will only flow if there's a source of...

  potential difference
• the cell has a store of ... energy, which is transferred to ... energy

  chemical, electrical
• what happens to electrical energy carried by electrons passing through components?

  it is transferred to other forms of energy
• potential difference


  the difference in electrical charge between two points
• what is potential difference measured in?

  volts (V) using a voltmeter connected in parallel
• potential difference in a series circuit is...


  ahared between components
• potential difference in a parallel circuit is...


  same across all components
• potential difference depends on...

  current and resistance
• potential difference (V) =

  current (A) x resistance (Ω)
• potential difference formula


  V=IR
• potential difference formula triangle

  
• what happens to potential difference when more cells are added?

  potential difference increases depending on the number of added cells
• total charge through a circuit depends on...

  current and time
• rate of flow of electrical charge

  size of electric current
• what is charged measured in?

  coulombs (C)
• what does one ampere of current equal to in charge?

  one coulomb of charge
• charge (C) =


  current (A) x time (s)
• charge formula


  Q=It
• charge formula triangle

  
• resistance is...


  the opposition to current flow
• resistance tells us...


  the potential difference required to drive a current through a component
• in a series circuit resistance...

  increases as more resistors are added
• in a parallel circuit resistance...

  decreases as more resistors are added
• resistor


  an electrical device that resists the flow of electrical current
• Ohm's law


  states that the electric current through a conductor between two points is directly proportional to the voltage across the two points
• resistance (Ω) =


  potential difference (V) / current (A)
• variable resistor


  a resistor whose value can be varied between its minimum and maximum values