230 people were selected in 7 18. International physics olympiad is an international physics competition for middle school students. 1967 was initiated by physicists from three eastern European countries, including Poland. * * * 7 18 contestants from 75 countries and regions participated in the competition, among which the competition was extremely difficult, and only 230 candidates were selected. The exam gives candidates five hours to answer questions related to the theme of commemorating Einstein's achievement of 100 in the 2005 World Year of Physics, with a full score of 20 points. Candidates can only be considered as excellent candidates if they pass the exam within three and a half hours, which shows that the difficulty of the exam is not generally great.