Final answer:
The Supreme Court case in which a farmer was fined for having a surplus of wheat was Wickard v. Filburn in 1942. The case established the authority of the federal government to regulate a farmer's personal production if it impacts interstate commerce.
Step-by-step explanation:
The Supreme Court case in which a farmer was fined for having a surplus of wheat was the case of Wickard v. Filburn in 1942.
In this case, Roscoe Filburn, a farmer in Ohio, was fined for exceeding his government-imposed wheat production quota. Filburn argued that the wheat was intended for personal use and not for sale, so it should not be subject to government regulation. However, the Supreme Court ruled that Filburn's excess wheat would still affect interstate commerce and therefore could be regulated by the government.
Wickard v. Filburn is an important case as it expanded the power of the federal government to regulate economic activity, even if it was an individual farmer's personal production.