- a.0-5%
- b.15-20%
- c.30-40%
- d.80-90%
Answer: (B) 15-20%
Answer as of 2024 — this may have changed since.
Ordinary commercial solar panels made of crystalline silicon convert roughly 15 to 20% of the sunlight falling on them into electricity (the best current modules reach a little over 22%), so option B is the accepted range. A single-junction silicon cell cannot exceed about 33% in theory (the Shockley-Queisser limit); efficiencies above 40% have been reached only by multi-junction cells in laboratories and on satellites, and 80 to 90% is impossible for photovoltaics. Solar cells work on the photovoltaic effect and are made mainly of silicon, a semiconductor. Related facts: the International Solar Alliance is headquartered at Gurugram, and India aims at 500 GW of non-fossil power capacity by 2030.