chapter 13-15 electricity

• electric current is the flow of electric charge through a conductor, measured in amps (A)
• electromotive force is the amount of energy supplied by the electrical source to each unit of electric charge
• ohm's law states that the voltage of a component is directly proportional to the current flowing through it
• resistance is directly proportional to length
• resistance is inversely proportional to cross-sectional area.
• series circuits


  electrical components are connected in a single branch.
• parallel circuits


  electrical components are connected in branches which splits from the main branch
• series circuits


  when one component spoils, the whole circuit stops working.

  current through the whole circuit is constant.

  sum of p.d. of all components is equal to emf.
• parallel circuit


  when a component spoils, components in other branches continue to work normally.

  current in each branch adds up to current from source.

  p.d. of each branch is equal to emf.
• resistance (R) = voltage (V)/ current (A)
• potential difference (V) = current (I) x resistance (R)