Concept:A hole is an unoccupied electron state (vacancy) in a nearly full valence band that acts as a positive charge carrier of charge \( +e = +1.6 \times 10^{-19}\text{ C} \).
Formula:$$q_{\text{hole}} = +e = +1.602 \times 10^{-19}\text{ C}$$
Solution:- When an electron leaves a covalent bond, the localized vacancy attracts electrons from neighboring bonds.
- The collective motion of valence electrons filling successive vacancies is mathematically equivalent to the movement of a single positive charge of \( +e \).
Why other options are incorrect:- Option A: Holes act as mobile charge carriers and are not electrically neutral.
- Option B: Free electrons have negative charge, whereas holes behave as positive charges.
- Option D: Holes have a well-defined finite effective mass determined by the curvature of the valence band.
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