Q. If solar energy Qr is available at a reservoir storage temperature of Tr and if quantity of heat Qa is transferred by the solar collector at temperature Ta, then which of the following is true?

• (A) first law efficiency = qa/qr
• (B) second law efficiency = exergy output / exergy input
• (C) second law efficiency = (first law efficiency)*(1-to/ta)/(1-to/tr)
• (D) all of the mentioned