UROP prerequisites vary based on the project/subfield. Sometimes they are explicitly listed for advertised UROP opportunities, as on elx.mit.edu. In Research Subfields, we try to provide more specific prerequisites based on the subfield of physics.

Most students, especially if it is your first UROP, are given computational projects. The best advice I can give is to learn one programming language and get good at it (Python, Julia, C, etc.). Good classes at MIT include 6.101. Often, the skills you learn in one language are easily transferable to another language, maybe modulo some annoying syntax differences. When you email PIs, be sure to indicate how well you know various computing languages.

If you are interested in any kind of physics experiment, I strongly recommend courses such as 6.2000/6.3000 (circuits and signal processing, respectively). It is very helpful to translate the electromagnetism you studied in physics into practical experiments from an engineer’s perspective. Many experimental projects will not expect you to have experience with the complex setups that the lab uses (probably nobody would have this experience!), but it is very helpful if you are familiar with common instruments in the lab such as oscilloscopes and spectrum analyzers. Also very helpful is knowing how to interact with these instruments using data capture and analysis methods in your favorite programming language.