Germanium and silicon behave as semiconductors because

The correct answer is Option (2) → the energy gap between their conduction and valence bands is of the order of 1 eV

Correct statement:

☀ the energy gap between their conduction and valence bands is of the order of 1 eV

Explanation: Germanium and silicon act as semiconductors because they have a small energy band gap (≈1 eV), which allows some electrons to jump from the valence band to the conduction band at room temperature, enabling limited conductivity.