Bach's Brandenburg Concerto no. 2 in F Major is based on the ritornello principle, which means that?

The ritornello principle is a fundamental concept in Baroque music, and it specifically refers to a structural form in which a recurring passage, or ritornello, alternates with contrasting episodes featuring solo instruments. In Bach's Brandenburg Concerto No. 2 in F Major, this principle is exemplified through the way that the ritornello theme is presented in various keys throughout the concerto, adding contrast and variety to the musical texture.

In this piece, the initial ritornello theme is played by the ensemble and is interspersed with sections where the soloists (trumpet, flute, oboe, and violin) introduce new material. This creates a dynamic interplay between the ensemble and the soloists, showcasing both the solo instruments and the full orchestra. As the piece progresses, the ritornello returns but may appear in different keys, creating a sense of development and contrast that is characteristic of the Baroque style.

While the other options might touch on aspects of musical form or texture, they do not capture the essence of the ritornello principle as accurately as the idea of varying instances of soloists and ritornello in different keys.