1. NO. A CHARGED PARTICLE HAVING ITS OWN VELOCITY MAY NOT MOVE ALONG AN ELECTRIC LINE OF FORCE.
The line of force in the electric field is the path along which a unit positive test charge will move if it is free to do so. If a positive charge is left freely in the electric field due to the charged sphere, it will always move normally away or towards the chargedsphere depending upon the nature of the charge in the sphere.
2. no.may not.
3. Depending on the distance, d. It is similar to behaviour of magents. If the distance is small, they will attract each other. If d is large, they don't.