WA education authorities have admitted that the Year 12 physics exam contained an error, despite rigorous proof-reading procedures.

A question stated that a system was “in equilibrium”, even though it was not.

Students who accepted that statement could have provided a simple solution. But the students who recognised the system was not in equilibrium and answered correctly would have had to spend twice as much time calculating the answer.

A physics teacher who did not want to be named said the error could potentially have put more able students at a disadvantage because they were more likely to notice it and spend more time on the problem.

“It says ‘at equilibrium’, which it clearly isn’t,” the teacher said.

“This makes the problem impossible to answer within the context of high school physics.”

School Curriculum and Standards Authority executive director Allan Blagaich said the question required students to apply principles they would have learnt in class to solve the problem.

“It is acknowledged that the system presented in question nine of the physics paper is not in equilibrium,” he said.

“There are two alternate calculation processes that can be used. Each process would provide a different answer.

Both processes and answers will be accepted by the markers as correct. No student will be disadvantaged.”

More than 3000 students sat the physics paper on November 1. Some teachers also raised concerns the physics exam may have included content that was not in the syllabus, including a reference to magnification.

Mr Blagaich said even though the word magnification app-eared in a comprehension question, the syllabus content that students needed to draw on related to science inquiry skills, which was examinable content.