My major gripe isn't so much the difficulty of the questions as the jumbled English the NESA examiners use at times. I often have to read the questions twice to make sure I understand what they want and even then I have chosen the wrong answer. For example the NSW 2019 HSC Physics Exam, Q17. Their answer is D, which suggests that the electrons will be pushed downwards towards Z below the current currying conductor (ccc), even though they started ABOVE the ccc.
From the wording of their question, the correct answer is B as electrons above the wire will always be pushed upwards depending on their velocity and the strength of the magnetic field. There is absolutely no way that the cathode rays (electrons) can deviate downwards from their starting position unless the current direction is reversed. I can only arrive at their solution if I use mangled English rather than the exact wording in their question.
The exam question asks "Which direction will this spot move towards if the resistance is increased?" Now the effect on the electrons is they will not deviate upwards by as much as if the current had remained at a higher amps (less current = reduced magnetic field intensity), but as I stated above they will never deviate downwards which is the given answer. So in effect what the examiners from NESA/BOSTES/BOS/(whatever they change their name to next week) should have asked is "What is the CHANGE in direction that the spot will move if the resistance is increased?" That's one lost mark for all the hard working students who knew their Module 6 but sadly could not read the minds of the boofheads at NESA.
This is in effect how the old style CR televisions worked, though the magnetic fields were supplied by 2 pairs of solenoid coils arranged to provide a horizontal and vertical field.
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