What is produced when current flows through a resistance?

When current flows through a resistance, heat energy is produced due to the resistance opposing the flow of electric current. This phenomenon is described by Joule's law, which states that the power of heat generated is proportional to the square of the current flowing through the resistor and its resistance (P = I²R). As electrons pass through the resistance, they collide with the atoms in the material, causing the atoms to vibrate and generate heat.

This conversion of electrical energy into thermal energy is a fundamental principle in resistive circuits and is essential in the operation of many electrical devices, such as electric heaters and incandescent light bulbs. Although other forms of energy like light, sound, or magnetism can also be produced under different circumstances (such as in light bulbs or when motors operate), in the context of current flowing specifically through a resistance, the predominant effect is the generation of heat.