Final answer:
Many atoms of silicon are involved in the photovoltaic process, as they are arranged in a large crystal lattice, each bonded to four other atoms. This network facilitates the movement of electrons that contribute to electric current generation.
Step-by-step explanation:
In regards to whether one atom of silicon is involved or many, in the context of semiconductor physics and specifically in silicon photovoltaic (PV) cells, it is not just one atom of silicon but rather a vast number of atoms.
Silicon cells, whether monocrystalline or polycrystalline, consist of a crystal lattice with an extensive network of silicon atoms, each atom bonded covalently with four adjacent atoms forming a tetrahedral structure.
The phenomenon of an electron's transition from the valence band to the conduction band, which is associated with the band gap energy of 1.1 eV, involves interactions within this extensive network of interconnected silicon atoms.
Such transitions contribute to the generation of electric current in a photovoltaic cell when exposed to sunlight. Due to the nature of silicon's crystalline structure, the correct answer would be that a large number of silicon atoms are involved.