1. Two particles have equal masses of 5.0 g each and opposite charges of +4.0 X 10-5 C and -4.0 X 10-5C. They are released from rest with a separation of 1.0 m between them. Find the speeds of the particles when the separation is reduced to 50 cm.

3. Consider a uniformly charged ring of radius R. Find the point on the axis where the electric field is maximum.

4. A circular wire-loop of radius 'a' carries a total charge Q distributed uniformly over its length. A small length dL of the wire is cut off. Find the electric field at the centre due to the remaining wire.

5. Positive charge Q is distributed uniformly along the positive y-axis between y=0 and y=a. A negative point charge -q lies on the positive x-axis, a distance x from the origin (a) Calculate the x- and y-components of the electric field produced by the charge distribution Q at points on the positive x-axis. (b) Calculate the x- and y- components of the force that the charge distribution Q exerts on q.

6. Positive charge Q is uniformly distributed around a semicircle of radius a. Find the electric field (magnitude and direction) at the center of curvature P.

7. A small sphere with mass m carries a positive charge q and is attached to one end of a silk fiber of length L. The other end of the fiber is attached to a large vertical insulating sheet that has a positive surface charge density a. when the sphere is in equilibrium. At what angle the fiber makes with the vertical sheet.