Online Physics Olympiad
Contents
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.
Visit the official website at: https://opho.physoly.tech/
Open Contest
The open round consists of 50+ 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 
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, 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 used at HMMT (Harvard-MIT Mathematics Tourney):
![\[w(n, N) = (0.9)^{i+j}[\exp(n/40) + \max(5.5 - \lfloor \ln{N} \rfloor, 2)],\]](http://latex.artofproblemsolving.com/9/e/5/9e5a7c0a10db7831534f03257088949257e4f308.png)
where 
(represents whether a team got it on the first try, second try, or third try) and 
(represents what day of the competition the team got the question on). Additionally, 
represents the number of teams that got the question right and 
represents the question number (in this regard, expect all questions to be ordered by difficulty). 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 
of 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 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 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.
