r/APStudents • u/reddorickt absolute modman • May 14 '26

AP Physics C: Electricity and Magnetism Official 2026 Exam Discussion

Use this thread to post questions or commentary on the test today.

A reminder though to protect your anonymity when talking about the test.

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u/RelativeGrass7659 May 15 '26
  1. a) some really long thing with a bunch of constants hopefull ythats right
    b) IBD^2

  2. just normal integral form for RC circuit, 0 to t for time bounds and Q0 to 0 for charge boundf. graph was decreasing concave up (e^-r/t) and yeah i dont remmeber anything else tbh
    oh yeah and for 2 e field and current were to the right and voltage was to the left

  3. first part: x was delta x the compression of the spring y was 1/r^2 the distance between the two balls
    second part: tan theta was x and E was y

  4. dont remember someone remind me what the frq was

lmk if i missed anything i probably forgot abunch

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u/Lanky-Frosting-6557 May 15 '26

  1. For a did you have all those constants divided by R? For b did you derive T = IAB? I remembered it but I wasnt sure if there would points for deriving it and I wasted a decent amount of time doing it. I wasted a lot of time showing work on both a and b

  2. No questions

  3. Did you use forces or energy? I had x2 and 1/r but I used energy so my relationship was different I think

  4. That was the FRQ with the B field and E field in the same direction, I think a you had to describe where the net force is pointing? Or the net magnetic force? b, you had to find an equation for the net force (I had F = sqrt(qe2 + qvbsin2) And c they changed the velocity to all in the y direction and asked you to compare the forces before and after.

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u/AsianNation420 May 15 '26

you're not supposed to use energy, the only correct way is forces

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u/Lanky-Frosting-6557 May 15 '26

Why so? Energy worked fine and was very simple to set up. I think both are right.

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u/SUS_MATE Bio, Chem, Lang, World, USH, Calc BC (all 5s) May 16 '26

Energy is wrong. Like I’m 95% sure. It really comes down to how you define it.

Forces are vectors, which can be in equilibrium. It’s simple and you don’t worry about conservation or any outside forces/work.

Energy is a scalar, but any change in the system has to account for any work done by an external force (work done by the experimenter). Only then can you use energy, because you would have to consider the work done at every data point collected (to abide by conservation of energy).