How do solar panels convert sunlight into electricity?

• A. Through the photovoltaic effect, where sunlight excites electrons in silicon, creating an electrical current.
• B. By heating water to produce steam.
• C. By absorbing mechanical vibrations.
• D. By chemical combustion of fuels.

Answer: (A)

Solar panels convert light to electricity through the photovoltaic effect in a semiconductor like silicon. When sunlight is absorbed, photons with enough energy push electrons from the valence band to the conduction band, creating electron–hole pairs. The built-in electric field at the p–n junction then separates these charges, driving electrons toward the n-type side and holes toward the p-type side. When the circuit is closed, this separation creates a current, producing direct current electricity. This is distinct from heating water to make steam, which is solar thermal energy; or extracting energy from vibrations, which is a different form of energy harvesting; or burning fuels, which is chemical energy release.