2.1.2 Electrical Charge & Current

• What must a closed circuit include for electrical charge to flow through it?

  A source of potential difference.
• What is current?

  The flow of electric charge.
• How is current size determined?

  By the rate of flow of electrical charge.
• charge flow = current x time
• current = charge flow / time
• time = charge flow / current
• What is the symbol for charge flow?

  Q.
• What is the symbol for current?

  I.
• What is the symbol for time?

  t.
• What is charge flow measured in?

  Coulombs (C).
• What is current measured in?

  Amperes (A).
• What is time measured in?

  Seconds (s).
• In a single closed loop, does the current differ at different points?

  No.
• A battery charger passes a current of 2A through a cell over a period of 2.5 hours. How much charge is transferred to the cell?

  18,000C.
• Q = I x t