United States Physics Olympics
The United States Physics Olympiad, or USAPhO, is comprised of 2 exams, the exam, or screening exam, and the semi-final exam. In 2008 and 2009, there was an additional quarter-final exam between the F=ma and semi-final. USAPhO is sometimes used to refer to just the semi-final exam, as it is the last of the national physics exams (and is thought of as analogous to USAMO).
exam
Any high school student who is either a US citizen or permanent resident is eligible to take this exam.
The test is 75 minutes long, with a total of 25 possible points. It is composed of 25 point multiple choice section each worth 1 point.
From the results of the exam, approximately the top 400 are chosen to participate in the United States Physics Olympiad Semi-final exam.
Semi-final Exam
Approximately the top 400 scorers on the preliminary exam are invited to take the semi-final exam. The purpose of this exam is to select the members of the US Physics Team.
The Semi-final exam is a 2 part, 3 hour exam. The exam contains 6 problems total, which may be broken into 4 in part A and 2 in part B or 3 in each part. All are free response problems. The content is any topic in the official IPhO syllabus.
The tests are the primary measure used to select the 20 members of the US Physics Team. Once selected, the top 20 students are invited to attend a training camp in May or June, from which the top 5 students and 1 alternate are selected to compete in the International Physics Olympiad, or IPhO as the US traveling team.
Sample Problems
Although the difficulty varies from year to year, both the and the semi-final exams from previous years can be found at [1].