1. A circular arc of radius a has charge Q distributed uniformly over its length. The are subtends an angle of n/Z radians from the origin, and the y-axis bisects the arc. Additionally, there is a positive point charge q on the y-axis at y = a. y (a) Find the value of Q in terms of q such that the total electric eld is zero at the origin. [b] If you were told to find the value of Q such that the total electric potential is zero at the origin, would you expect your answer to be the same as your answer to Part [a]? Explain. (Note: you do not need to calculate anything for this part] 2. Negative charge Q is distributed uniformly on the y-axis between y = L and y = L. What is the change in electric potential energy if a positive point charge (.1, initially located infinitely far away, is moved to the point (L, L / 2)? 3. An insulating spherical shell with inner radius R and outer radius 2R carries a nonuniform volume charge density p('r) = pOR/r, where p0 is a positive constant and r is the distance from the center of the shell. A point charge q is located at the center of the shell. 2R ,% q 90") Find the value of q in terms of po and R such that the magnitude of the electric field is constant in the region R