Change, Current and Time

• What is the definition of charge?

  Charge is a measure of total current over time
• How can charge be compared to water flow?

  Charge is like total water flowing down a hill
• What symbol represents charge?

  The letter q
• In what unit is charge measured?

  In coulombs
• What is the equation for charge?

  Charge equals current multiplied by time
• If a kettle draws 12 amps for 50 seconds, how much charge passes through the wire?

  600 coulombs
• How do you find the current if the charge is 43.2 kilo coulombs over two hours?

  Rearrange to i = q / t
• How do you convert kilo coulombs to coulombs?

  Multiply by 1000
• How do you convert hours to seconds?

  Multiply hours by 3600
• What is the current if 43,200 coulombs are transferred in 7,200 seconds?

  6 amps
• What is the relationship between charge, current, and time?

  • Charge (q) = Current (i) × Time (t)
  • Current is measured in amps (A)
  • Time is measured in seconds (s)
• How do you solve for current when given charge and time?

  1. Use the equation i = q / t
  2. Convert units if necessary
  3. Plug in values and calculate