## 1. Participation and categories

- Náboj Physics is a team competition for high-school students and students of corresponding grades of 8-year grammar schools. Teams consist of four or five members. All members of any single team come from the same school.
- Teams compete in two categories - Seniors and Juniors. Only teams the members of which do not attend the highest grade of a high school and the grade immediately preceding to it are allowed to compete in the Juniors category. High-school teams with arbitrary age composition can compete in the Seniors category.

## 2. Registration and the waiting list

- Teams sign up for the competition via the web site during the registration period. It is possible to change team members after the team has been registered. The changes are allowed until the end of the registration period. The organisers reserve the right to replace any team not complying the “minimum number of members” requirement by a team from the waiting list after the end of the registration period.
- Upon registration, the team chooses a venue within its country. It is not allowed to compete abroad.
- In case a full capacity of the venue is reached, the team is placed on the waiting list.
- Any single school can register at most two teams into each category. Any other team from the same school is placed on the waiting list, and it will be involved in the competition only if the venue’s full capacity is not reached at the end of the registration period.
- If the capacity is extended or some spots are vacated after the full capacity has been reached previously, the teams are taken from the waiting list, respecting the order in which they have signed up for the competition. The teams that have not reached the “two teams per category” limit are prioritized, though. Organizers reserve the right to move any team from the waiting list to the competition out of the order in justified situations.
- All information regarding dates, numbers of registered teams, and overal capacities are available on the web site.

## 3. The competition start

- The contestants are required to arrive at the competition location in time and to respect instructions of the organizers.
- Before the competition starts, every team obtains a sealed envelope containing the first eight problems. They are allowed to open it only on organizers’ permission. This action starts the competition.

## 4. Solving of the problems

- The contestants can solve any of the eight problems, which are available to them. The result is usually a single numeric value or a mathematical expression.
- As soon as a team concludes that the result is correct, one team member goes to the correctors’ point with the result written on the paper with the problem statement to submit the solution for checking. The corrector assesses the solution and marks it with a corresponding mark.
- A number of trials to submit the solution is not limited. However, after three unsuccessful trials, a corrector can require the contestant to present the full solution.

## 5. Correctors and problem exchangers

- Correctors assess solutions; problem exchangers give out new problems to teams after any of the problems has been solved correctly.
- There are usually several correctors, and each of them checks only specific problems. Details will be explained on a site before the start of the competition. If several contestants arrive at the same corrector at the same time, they are accepted in the order in which they have arrived.
- A problem statement with a correct result marked by a corrector is handed to problem exchangers. Only problems submitted to them are considered as solved.
- Upon submitting to the exchangers, a team obtain a new problem, unless all prepared problems have been given out to them already. A total number of prepared problems will be announced before the start of the competition.
- If a contestant does not agree with corrector’s decision, they can discuss their solution with the chief physicist.

## 6. The competition end

- The competition lasts two hours. After expiration of the time limit, it is not further possible to queue at the correctors’ point.
- The contestants already waiting in the queue at the moment of expiration of the time limit can submit their solutions. Any eventual correct solutions are considered to be submitted at the time of the end of the competition.

## 7. The winner

- The winner in each category at particular venue is a local team which solved the highest number of problems.
- Should several teams solve the same number of problems, the team with the highest ordinal number of a solved problem wins. If it does not break the tie, solved problems with second highest ordinal numbers are compared, etc.
- If several teams solve identical set of problems, the team with the earliest time of submission of the latest solved problem wins. In case these times are identical, the earlier submission time of the second latest solved problem decides, etc.
- The same method is applied to determine the order of the rest of the teams.
- The same principles are used when determining the national and international results.

## 8. Permitted tools

- Each team obtains a table of constants before the competition start.
- Contestants can bring paper, ordinary writing instruments, drawing utensils and calculators. It is also permitted to use any printed literature, except for the booklets of previous Nábojs Physics and the materials derived from them.
- A usage of any kind of long-distance communication means (mobile phones, internet etc.) is prohibited. A cooperation is allowed only within a team.

## 9. Statute of the Rules

- These Rules are obligatory for all participating teams regardless of the competition venue. By the registration, the team confirm that they have read and understood the Rules, and that they will comply with them during the competition. Failure to comply with the Rules may result in disqualification of the team.