Textbook Problem

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 sucrose (C₁₂H₂₂O_1l) per hour per hectare (1 ha = 10.000 m²). Assuming that sucrose is produced by the reaction

$12{\text{CO}}_2\left(g\right)+11{\text{H}}_2\text{O}\left(l\right)\to {\text{C}}_{12}{\text{H}}_{22}{\text{O}}_{11}\left(s\right)+12{\text{O}}_2\left(g\right)\Delta H=5640\text{KJ}$

calculate the percentage of sunlight used to produce the sucrose—that is, determine the efficiency of photosynthesis.