What happens to electron emission as the filament temperature increases?

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Multiple Choice

What happens to electron emission as the filament temperature increases?

When the filament is heated, more electrons gain enough energy to overcome the work function and escape from the surface. This thermionic emission increases as temperature rises because the energy distribution of electrons shifts so a larger fraction have energy above the barrier. The relationship is described by the Richardson-Dushman form, J ≈ A T^2 exp(-φ/kT); as temperature T increases, the exponential term becomes less restrictive, causing a rapid rise in emitted current. So, emission grows with temperature, not stays the same, decreases, or varies randomly. The increase is not perfectly linear, but the overall trend is clear: higher temperature yields more emission.

When the filament is heated, more electrons gain enough energy to overcome the work function and escape from the surface. This thermionic emission increases as temperature rises because the energy distribution of electrons shifts so a larger fraction have energy above the barrier. The relationship is described by the Richardson-Dushman form, J ≈ A T^2 exp(-φ/kT); as temperature T increases, the exponential term becomes less restrictive, causing a rapid rise in emitted current. So, emission grows with temperature, not stays the same, decreases, or varies randomly. The increase is not perfectly linear, but the overall trend is clear: higher temperature yields more emission.

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