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  1. K

    Potential and field at two electric plates

    and the other answers are wrong, correct?
  2. K

    Capacitor network finding potential

    3.1E-6 is from series. so you add them by 1/C and the answer is 1/c. so for the first one i did 1/8.6E-6 + 1/4.8E-6 = 1/C where C is 3.1E-6 4.1E-6 is also from series. i did 1/6.2E-6 + 1/11.8E-6 = 1/C where C is 4.1E-6. 7.6E-6 is parallel so you just add them. i added 4.1E-6 to 3.5E-6
  3. K

    Capacitor network finding potential

    final capacitance = 1.48E-5 F. i combined 3.1E-6, 4.1E-6 and 7.6E-6
  4. K

    Capacitor network finding potential

    i did this in three steps. i found C from the first two as a series. then i found c from the top two as a series. then i used my answer from the top two and the lower capacitator as a parallel network. so in the last calculation i did 4E-6. AH! there is my mistake. before i had my old...
  5. K

    Capacitor network finding potential

    3.1e-6 + 4e-6 + 4.9e-6
  6. K

    Capacitor network finding potential

    ok. adding all the Cs gives me 1.2E-5. i plugged this into the formula U=.5CV^2. for v i used 12 and solved for u
  7. K

    Capacitor network finding potential

    my bad. i dont know what i did wrong, but i redid it and got u=8.64E-4.
  8. K

    Capacitor network finding potential

    i then got a total capatance of 1.21E-5 F and a total energy of 0.0027 J
  9. K

    Capacitor network finding potential

    i re-did it and got 4E-6. is this right?
  10. K

    Capacitor network finding potential

    For the capacitor network shown in the figure, the potential difference across ab is 12V. Find (a) the total energy stored in this network and (b) the energy stored in the 4.8 uF capacitor. figure: http://i.imgur.com/Wxbuu.png ATTEMPT: PART A: i first did the leftmost 2 capacitors...
  11. K

    Charge sprayed onto a conductor

    An irregular neutral conductor has a hollow cavity inside of it and is insulated from its surroundings. An excess charge of 16.0 nC is sprayed onto this conductor. A) Find the charge on the inner surface of the conductor. B) Find the charge on the outer surface of the conductor. C) Without...
  12. K

    Electric flux through a cube

    A point charge 6.50 nC is at the center of a cube with sides of length 0.260 m. PART A: What is the electric flux through the surface of the cube? PART B: What is the electric flux through one of the six faces of the cube? ATTEMPT: A) Total flux enclosed by the cube = Q / eo...
  13. K

    Traveling proton and electric field problem

    A proton is traveling horizontally to the right at 4.20×106 m/s. Find (a)the magnitude and (b) direction (counterclockwise from the left direction) of the weakest electric field that can bring the proton uniformly to rest over a distance of 3.40 cm. Part C: How much time does it take the...
  14. K

    Uniform charged ball charge density problem

    my last response's answer is in C/m^3. (2.387E-6) is this one right?
  15. K

    Simple electric flux through tetrahedron problem

    yes. and the sides are positive. thank you
  16. K

    Simple electric flux through tetrahedron problem

    for a closed surface outward is positive
  17. K

    Three negative point charges lie along a line

    thank you. my mistake. for the magnitude i got 1.04E7 N/C. i found the x components of E for the charges. I know that there is no net E in the Y direction. then i added those x components up. is this correct? (1.04E7 N/C)
  18. K

    Uniform charged ball charge density problem

    ok so, retrying part A i used A=(4/3)(pi)r^3 and got A=0.0335. so my new answer is 8E-8/0.0335=2.387E-6. is this right for part A?
  19. K

    Three negative point charges lie along a line

    Three negative point charges lie along a line as shown in the figure. figure: http://tinyurl.com/7xppvc8 Find the magnitude and direction of the electric field this combination of charges produces at point , which lies 6.00 from the charge measured perpendicular to the line connecting the...
  20. K

    Simple electric flux through tetrahedron problem

    the convention is positive sign?
  21. K

    Uniform charged ball charge density problem

    A 20-cm radius ball is uniformly charged to 80 nC. (a) What is the ball’s charge density (C/m3)? (b) How much charge is enclosed by spheres at points 5, 10 and 20 cm from the center? (c) What is the electric field strength at points 5, 10 and 20 cm from the center? ATTEMPT: part a: i...
  22. K

    Coulomb's law electric field charge on y axis

    ok, i don't know how to start. my initial thought is that E on the x-axis is zero. the three charges pull in the y direction. i can't see anything that would pull/push in the x-direction. is this right?
  23. K

    Coulomb's law electric field charge on y axis

    just kidding you are right. i didnt read the first part that the charges are "on the y axis"
  24. K

    Coulomb's law electric field charge on y axis

    (3,0) and (0,0) are both at y=0 yet they are in two different places.
  25. K

    Coulomb's law electric field charge on y axis

    you said "All three charges are along the y-axis. The +2q charge also lies on the x-axis." why did you say "also"?
  26. K

    Simple electric flux through tetrahedron problem

    A tetrahedron has an equilateral triangle base with 20-cm-long edges and three equilateral triangle sides. The base is parallel to the ground and a vertical uniform electric field of strength 200 N/C passes upward through the object. (a) What is the electric flux through the base? (b) What is...
  27. K

    Coulomb's law electric field charge on y axis

    Is this question worded poorly or is it just me? Three charges are on the y-axis. Charges -q are at y = ±d and charge + 2q is at y = 0. (a) Determine the electric field E along the x-axis. (b) Verify that your answers to part a has the expected behavior as x becomes very small and very...
  28. K

    Maximum initial speed the electron can have without hitting the negative plate

    The acceleration = F/m = E*q/m So at y max vy = 0 so vy^2 = vy0^2 - 2*E*q/m*ymax So vy0 = sqrt(2*E*q/m*ymax) = sqrt(2*1.20x10^4*1.60x10^-19/9.11x10^-31… = 9.18x10^6m/s So v0 = vy0/sin(45) = 9.18x10^6m/s/sin(45) = 1.30x10^7m/s
  29. K

    Maximum initial speed the electron can have without hitting the negative plate

    Two parallel plates are 2.0 cm apart and the electric field strength between them is 1.0 × 10^4 N/C. An electron is launched at a 45 degree angle from the positive plate. What is the maximum initial speed v0 the electron can have without hitting the negative plate? i think the answer is...
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