Excess Photon Energy Is Not an Extra Level - Semiconductor Physics: Bands, Doping, and Junctions Step by Step

Above-gap energy is recorded as excess in the toy ledger. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

A higher-frequency photon has more energy than the gap

Frequency 4 hertz gives photon energy 8 joules.

E=2\cdot 4=8\ \mathrm{J}

The extra energy is a ledger entry, not a new level

The gap uses 6 joules, leaving excess 2 joules in this toy accounting.

\mathrm{excess}=8 - 6=2\ \mathrm{J}