Alex Zhai is one of just 158 students nationwide still in the running to represent the U.S. at the International Physics Olympiad this summer. He has represented the U.S. twice at the Math Olympiad. Gargoyle photo by Sindha Agha (click to enlarge)

ALEX ZHAI IS used to being one of the top math students in the country, having represented the United States twice at the International Mathematical Olympiad.

Now, he's taken his place among the nation's top physics students as well, according to results announced this week by the American Association of Physics Teachers.

Zhai, a senior, is one of only 158 students from around the country — and one of 16 from Illinois high schools — to advance to the semifinals of the U.S. Physics Team selection process. Zhai took the quarterfinal exam about a week ago.

The students are competing for a spot on the 24-member team, from which five students will be selected to represent the United States at the International Physics Olympiad this summer in Vietnam.

To qualify for the semifinal round, Zhai had to take a 60-minute free response exam that covered AP Physics C material on mechanics and electrostatics. He was one of 415 students who took the exam. Uni physics teacher Jim Carrubba is Zhai's faculty sponsor.

Zhai's next exam, to qualify for the U.S. Physics Team, must be taken by March 19. The exam will consist of two free-response parts: Part A, which gives four problems with a 90-minute time limit, and Part B, which gives two problems with a 90-minute time limit.

The exam will cover topics in introductory physics including mechanics, E&M, thermodynamics and fluids, relativity, nuclear and atomic physics, and waves and optics. There is also a one-problem Part C with a 20-minute time limit that will not count toward selection for the physics team, but participants will be awarded a special prize for solving the problem correctly.

The top 24 students based on the semifinal stage will become members of the U.S. Physics Team, with five to be selected to compete in the 39th International Physics Olympiad, which will take place July 20 to 29 in Hanoi.

This is the first time Zhai has competed in the physics selection process. During the past two summers he has represented the United States at the International Mathematical Olympiad, and he is aiming for a third appearance. The 49th IMO will be held July 10 to 22 in Madrid, Spain, overlapping the physics competition.

"There's a scheduling conflict between the international math and physics Olympiads, so it's only possible for me to do one this year," said Zhai. "I don't know whether I can get that far in physics, but it could be a decision to make in a few months."

In 2006 Zhai won a silver medal at the IMO, which was held in Ljubljana, Slovenia. Last summer he won a gold medal and finished seventh overall. The 2007 IMO was held, coincidentally, in Hanoi.