The selection of participants for international physics competitions is a long drawn process and involves state level and national level screen tests. At the state level, students from different schools have to sit for an examination which involves solving a few problems using the laws of physics. For some physics competitions students who form the top percentile qualify for the national level screening, in other competitions, cut off marks are specified and students who score more than cut off marks qualify for the national level tests. The qualifying state level students often are supported by the best state level teachers and receive additional coaching to help them excel at the national level.
For physics competitions at the national level, the questions are more difficult and test the students understanding of the basic principles of physics. In a state, most students have studied the same syllabus in school, but at the national level, there can be significant differences in the knowledge levels as well as learning methods used by the students. The competition duration is usually for two or three hours, with only a few problems to be solved. However, many of the questions are unconventional, and some amount of imagination is needed to visualize the problem before even attempting to solve it. Often there are multiple ways of solving the problem.Even if the participant does not arrive at the correct answer, they may be given marks for solving part of the question correctly.
Often the winners of national level physics competitions again receive intensive coaching from the most experienced and knowledgeable physics teachers in the country, before they participate in international physics competitions. The team size and participation in international physics competitions depends to some extent on the economic conditions prevalent, with large, developed countries participating in international level competitions but small undeveloped poor countries will not be able to participate.