EE140 Mid-Term 1 Dr. Ray Kwok Print Name : _______________________________________________________________________ 1. A uniformly charged disc with radius R is placed at a distance d above an infinite ground plane. (a) What is the electric field at a distance z < d above the ground plane along the z-axis? (b) Using the definition of  dEV, find the electric potential at the same location (z above the ground plane). (c) What is the capacitance of this configuration (disc above the ground plane)? d z OEE140 Mid-Term 1 Dr. Ray Kwok 2. An infinitely long thin sheet with width W is bent into a semi-circle. The total current I, uniformly distributed along the curve, is coming out of the page as shown. Find the magnetic field vector at the origin, in terms of I and W only. . . . . . x y . . . . . . oEE140 Mid-Term 1 Dr. Ray Kwok 3. A line charge of length L along the z-axis (from z = -L/2 to L/2) has a linear charge density of = |z|. What is the electric potential and electric field intensity at a distance x away from the center