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I'm trying to understand how lamps work.

I have read that the way this happens is when voltage is applied. The free electrons move due to the electromotive force (EMF), and when they collide with the lattice filament inside the lamp, they push the electrons in the lattice's atoms to a higher energetic state.

My question is how do electrons absorb energy to transition to a higher energetic state (by getting repelled by other free electrons) or is there something happening under the hood that I'm still unaware of?

BioPhysicist
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Marouane Elalama
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1 Answers1

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The EMF, $\varepsilon$, corresponds to an electric field $\mathbf{E}$ within the lamp circuit. Neglecting induction, $$ \varepsilon = \int_A^B \mathbf{E} \cdot d \mathbf{l} .$$ This field does work on electrons as they travel from terminal B through the lamp to terminal A. Within the filament the kinetic energy of the electrons is dissipated through resistivity (corresponding to collisions). The filament is therefore heated and emits light.

The potential energy of the electrons is raised in the EMF source, typically through induction or chemistry.

FTT
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