An insulating sphere with radius r=0.1m that carries total charge q=1nc (uniformly distributed). the center of the sphere is located 0.2m above a large plastic sheet that has a uniform surface charge density =-8nc/m2 on one side. find the location of all points where the resultant electric field is zero, or show that there are no such points.

(2) (a) you have a simple circuit that consists of only a battery (δvbat=1.5v) and two resistors with resistance r1=10ω and r2=5ω, connected in series with each other. what is the current running through the battery? (b) you re-arrange your circuit so now r2 is attached in parallel to r1 rather than in series. what is the current running through the battery? (c) you add an additional resistor r3=7ω on the same branch as r2. what is the current running through the battery? (d) what is the power dissipated in r3?