Question

Assume that sunlight deposits 250 W/m2 of energy on a corn field, averaging over the day/night cycle. There are 4.186 joules per calorie. How many calories of energy are deposited on a square meter of field over the growing season? Now guess how many ears of corn grow per square meter, and guess what is the number of calories you get for eating an ear of corn. The word "calorie", when you see it on a food label, actually means "kilocalories", thousands of calories, so if you guess 100 food-label-calories, you are actually guessing 100,000 true calories or 100 kcal. Compare the sunlight energy with the corn energy to get the efficiency.

Answer 1