Wednesday, September 8, 2010

Notes on Current Electricity (Blog 1)

Wednesday, September 8, 2010
Physics textbook: pages 544-552

  • a flow of electrons is called an electric current
  • a current, much like a water current, flows from a positive terminal to a negative terminal
  • equation for a current: I = Q/t, where I represents current in amperes, Q represents the quantity of the current, represents time in seconds
  • an ammeter is used to measure currents of two types: direct current (DC) and alternating current (AC)
  • DC: the current flows in one direction from a power supply (ex. battery) to the load (ex. lightbulb), then back to the power supply
  • AC: the current has electrons that reverse because of electric and magnetic fields; the path of the current is also known as a circuit
  • the equation to show the electric potential difference used is V = E/Q; V is the electric potential difference in volts, E is energy in joules, and Q is the charge in coulombs
  • the equation E = Vlt calculates the energy transferred by charge flow
  • a voltmeter is used to measure potential difference
  • throughout the world, there are many different ways to convert energy from chemical, mechanical, thermal, and light to electric potential energy; wind, coal, oil, nuclear plants, and solar energy, among many examples, may be used


1 comment: