Recent content by chopticks

  1. C

    How does the energy change in a capacitor with variable plate distance?

    ok. If I want to find the maximum energy/volume then the distance doesn't matter, right?
  2. C

    How does the energy change in a capacitor with variable plate distance?

    Homework Statement A capacitor has variable distance between the plates . It charges with a constant charge Q and the distance between the plates increase with 20%. How many percent does the energy change in the electric field between the plates? Homework Equations E = (1/2)QV =...
  3. C

    Max Electric Field on 4.3mC Ring of Charge: Radius 4cm

    now I get the same answer as you=), thanks a lot!
  4. C

    Max Electric Field on 4.3mC Ring of Charge: Radius 4cm

    instead of differentiate, I plot the function in an graph. accodring to the graph there is only on max point where x is approx 0.12m and the electric fields is 4.246*10^18N/C. The electric field is etremley high but since the charge of the ring is 4.3mC it is quite reasonable. Is it physical...
  5. C

    Capacitors in parallel and in series

    The problem: A capacitor has the capacitance 35nF, the tolerance is max 10V. You have to put 30V over the capacitor . How many capacitors of same kind do you need if you want to achieve same C(35nF) that tolerate 30V? I have translated it from swedish to english, sorry if my english isn't so...
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    Max Electric Field on 4.3mC Ring of Charge: Radius 4cm

    The problem statement: Determine the maximum electric field on the axis of a ring of charge 4.3mC. The radius is 4cm. I think the key is to use ekvation 1 and derivate to determine the maximum electric field but I'm not sure. Q is the charge, x is axis of the ring, a is the radius. Any...