Electricity

• How does current act in a series circuit?


  The current is the same throughout
• What direction is the conventional current?


  Left <
• What do we measure current with?


  An ammeter
• What is the unit and symbol for current?


  Amps/Amperes Symbol is I in an equation
• How does current act in a parallel circuit?


  The current of the branches adds up to the current leaving the cell - eg 0.3A leaving cell meaning if upper branch is 0.2A then the bottom branch is 0.1A
• What does one volt represent?


  One joule of energy transferred per coulomb of charge
• How does potential difference (voltage) act in a series circuit?


  The voltage is shared between components eg 9V leaving cell and 2 bulbs - each bulb has 4.5V
• How does potential difference act in a parallel circuit?

  Each individual branch has the same TOTAL p.d with the p.d leaving the cell EG 12v leaving cell and 1 bulb on one branch and 2 bulb on second branch. Both branches individually add up to 12 v but the second branch has 2 bulbs so each bulb is 6v adding to the total of 12v
• How should cells be placed and issues?


  They should be in the same direction typically left. If one is in the wrong direction, it will cancel itself and another cell out.
• What unit is electrical charge measured in and how do we determine the size of the electrical current?


  coulombs (C) a current of one ampere means 1 coulomb of charge flowing per second
• What equation links charge flow, current and time and what are the units for it


  Q=IT Q charge flow Coulombs/C, current Amperes, time Seconds
• What equation links energy transferred, charge flow and potential difference and give the units etc


  E=QV E energy transferred Joules, Q charge flow C, V potential difference Volts
• Which equation links potential difference, current and resistance


  V=IR v voltage/potential difference, I current Amperes, R resistance ohms weird shape Ω