Simple Circuits Curriculum

Section 4: Endnotes

  • 1 The physics term that is used to specify brightness is power. That is the amount of energy generated by the bulb each second and is measured in watts. A 100 watt bulb generates 100 joules (energy or work) each second.
  • 2 A wire can have a lot of current flowing along it and give off heat energy but not necessarily light energy. If a voltage differential between the two ends of a wire filament is maintained, the wire with the least resistance would generate the most heat (as in a short circuit). This wire would not necessarily glow the brightest, though, because the power achieved depends upon the relative rate of flow of thermal energy in AND out of the wire (Power = Current x Voltage Drop) and while this wire would have the greater thermal energy flow in, greater surface area means that it would also have a higher rate of heat flow out.