The sun supplies energy at a rate of about 1.0 kilowatt per square meter of surface area (1 watt = 1 J/s). The plants in an agricultural field produce the equivalent of 20 kg of sucrose (C12H22O11) per hour per hectare (1 ha = 10,000 m2). Assuming that sucrose is produced by the reaction
12CO2(g) + 11H2O(l) → C12H22O11(s) + 12O2(g) ΔH = 5640 kJ
Calculate the percentage of sunlight used to produce the sucrose—that is, determine the efficiency of photosynthesis.