There are two papers in the Preliminary Examination of UPSC: General Studies Paper I and General Studies Paper II (CSAT). The first paper covers a diverse range of subjects including current affairs, history, geography, and environment, while the second paper assesses a candidate's comprehension, logical reasoning, and analytical capabilities. Both papers are of objective type format and are crucial in determining whether a candidate qualifies for the Main Examination. Performance in these papers is key to progressing in the examination process.