The space between the outermost filled energy band and the next empty band is called ………. a.conduction bandb.none of thesec.valence band d.forbidden zone

The space between the outermost filled energy band and the next empty band in a material is referred to as the "forbidden zone." This term defines the energy gap where no electron states can exist, which is crucial in determining the electrical and optical properties of materials.

1. Conduction Band: This refers to the band where electrons are free to move, allowing electrical conductivity.
2. Valence Band: This is the highest range of energies of electrons in a solid where electrons are normally present.
3. Forbidden Zone: This is the correct answer; it is the energy gap between the valence band and conduction band where no energy states are available for electrons.

Final Answer

The correct answer is d. forbidden zone.