A right isosceles triangle of side 2d has charges q, +2q and -q arranged on its vertices (see sketch). (a) What is the electric field at point P, midway along the lineconnecting the +q and -q charges? (b) What is the potential at P, assuming the potential to be zero at infinity? (c) How much work to bring a charge +4Q from infinity to the point P? A right isosceles triangle of side 2d has charges q, +2q and -q arranged on its vertices (see sketch).

Points A and B are 40 and 25 mm away from a 6 μC charge, how much work is necessary to do against the electric field (through external forces) to move a 5 μC charge from point A to point B?

Two point charges are 1m apart. Q1 = –8µC and Q2 = +5µC. Point P is 0.5m directly above Q2   a) How many electrons are needed to make –8µC of charge? b) What is the magnitude of the electric force between the two charges, and is it attractive or repulsive?  c) What is the electric potential V at point P due to the two charges? (Hint: this is a scalar quantity, no vectors needed.)  What is the magnitude and direction of the electric field E2 from Q2 only at point P?

In the figure set V = 0 at infinity and let the particles have charges q1 = +q = -5.00×10-5 C and q2 = -5q. They are seperated by d = 50 cm, with q1 located at the origin. Locate any points on the x axis (other that at infinity) at which the net potential due to the two particles in zero. What is the positive position? What is a negative position?

In Figure (a), we move an electron from an infinite distance to a point at distance R = 2.50 cm from a tiny charged ball. The move requires work W = 2.81 × 10-13 J by us. (a) What is the charge Q on the ball? In Figure (b), the ball has been sliced up and the slices spread out so that an equal amount of charge is at the hour positions on a circular clock face of radius R = 2.50 cm. Now the electron is brought from an infinite distance to the center of the circle. (b) With that addition of the electron to the system of 12 charged particles, what is the change in the electric potential energy of the system? (a) Number i (b) Number i |R-| (a) Units Units < Det er (b) < A