# Online Physics Olympiad

## Introduction

The Online Physics Olympiad (OPhO) is one of the largest online run physics olympiads in the world. This contest is a team based contest with each team consisting of 1-3 high school students. Undergraduate students in university may also participate, but they will be in a separate division and are not able to qualify for prizes.

## Open Contest

Thegch consists of 30+ numerical questions from various categories in physics including mechanics, electromagnetism, thermodynamics, relativity, waves, and more. Teams will work to compete over the course of five days to qualify for the \textit{Invitational Contest}, which will be held the following week. Please see Section $3$ for more details. Competitors will submit their solutions via an on-line submission portal. Difficulty of the contest will be ranging from AP Physics to IPhO.

## Submission Portal

On the submission portal, each contestant has three times to submit their answer. Note that correct answers will immediately be logged by the program. Most importantly, $\textbf{for any decimal answers, please round your answer to three significant digits}$!! Generally, more digits are better than less digits.


## Scoring

The base score for each problem is dependent on the difficulty which in turn is decided by the number of people who successfully answered it. Each incorrect attempt will decrease the base score and teams will be awarded bonus points for correctly solving it quickly. \\

The scoring mechanism is heavily based off of the one at HMMT: $w(n, N) = (0.9)^{i}[\exp(n/30) + \max(8 - \lfloor \ln{N} \rfloor, 2)] + \frac{3}{10}k,$ where $i \in \{0,1,2\}$ (represents whether a team got it on the first try, second try, or third try) and $k \in \{0, 1, 2, \cdots , 10\}$ which gives a bonus to the first $10$ teams who submit a solution to a problem correctly . The cumulative score of a submission will be determined by the sum of these values. With this scoring system, ties will be very unlikely. Note that the scoring system is subject to change, so if there is any type of edits we want to make we will do so before the start of the contest.

## Invitational Contest

Approximately the top $10$ teams from the Open Contest will be invited to compete in the Invitational Exam. The Invitational Competition will be a three day Olympiad style physics competition. Invitees will be required to write their solutions either handwritten or on a LaTeX compiler (we prefer the latter because many times handwritten solutions are hard to read). For information on an online LaTeX compiler, please visit \url{http://www.overleaf.com}.

## Submission of Test Papers

If a team qualifies for the Open Contest, we will e-mail the Invitational Contest to them from \url{opho@physoly.tech}. Once a team is finished with write-up of their solutions, they will be asked to submit them to a survey, which will be provided to them via e-mail.

## Scoring

Scoring for the invitational competition will be done by the OPhO Lead Organizers. They will each grade a submission's solution out of the points value of the individual problem and then sum all of your scores together. The cumulative sum of your scores over the entire exam will be the submission's final score which will be used to determine prizes.

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