Recent content by rofldude188

  1. rofldude188

    Faraday's Law - Balloon Problem

    Yeah you're right for the first part I need to plug in t = 0. Sorry I misread I thought z was along the horizontal axis but I now see it's along the vertical axis. So in this case you would find the new radius $$r_z^2 = r^2 + z^2$$ and then find area of that circle with respect to time and go...
  2. rofldude188

    Faraday's Law - Balloon Problem

    a) Calculate the proposed induced emf along the equator of the balloon. (horizontal equator), at the moment indicated above. $$V(t) = V + Ft \implies \frac{4 \pi r^3(t)}{3} = V + Ft \implies r(t) = \sqrt[3]{\frac{3V+3Ft}{4 \pi}}$$ $$\phi = B \pi r^2(t) = B\pi (\frac{3V+3Ft}{4 \pi})^{2/3}$$...
  3. rofldude188

    Capacitor Problem with distance-dependent dieletric

    That makes complete sense thank you.
  4. rofldude188

    Capacitor Problem with distance-dependent dieletric

    a) Find Electric Field at any point in the dieletric in the terms of the parameters given Making a pillbox Gaussian surface with one end in the conductor where E = 0 and the other end in the dieletric we have that $$\oint D \cdot dS = \rho_s A \implies D = \rho_s \implies E = \frac{Q}{A...
  5. rofldude188

    Solving Dielectric Problem: Electric Field & Charge Density

    a) Find the electric field in space For r < R (where R is the radius of the gold ball), E = 0 because the gold ball is a conductor. For r > R, let us make a Gaussian surface. $$\int \vec{D} \cdot \vec{dS} = Q_{free} \implies \vec{D} = \frac{Q}{4 \pi r^2}$$ Now this is a bit hand wavy but the...
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