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Illustration Joule Heating: Resistors Heat Up to Different Extents

Joule heating: resistors heat up to different extents
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Joule heating (also called ohmic heating) is caused by collisions of the charge carriers of the electric current \(I\) with the atoms. A constant voltage \(U\) is applied to two different resistors \(R_1\) and \(R_2\).
  • The resistance \(R_1\) is made of aluminum (Al) and is smaller than \(R_2\)
  • The resistor \(R_2\) is made of plumbium (Pb), i.e. lead.

The constant current \(I\) passing through the two resistors heats the larger resistor \(R_2\) more than \(R_1\). The larger resistor \(R_2\) glows, while \(R_1\) hardly heats up compared to \(R_2\).