# elect and magn

posted by
**Anonymous**
.

a postive charge of q is located at x=0 and y=-a, and a negative charge -q is located at the point x=0 and y=+a. A.) derive an expression for the potential V at points on the y-axis as a function of the coordinate y. take V to be zero at an infinite distance from the charges. B.) graph V at points on the y-axis as a function of y over the range from y=-4a to y=4a. C.) show that for y>a, the potential at a point on the positive y-axis is given by V=-(1/4piE_0)2qa/y^2.