Two identical pith balls supported by insulating threads hang side by side and close together,as shown below. One is positively charged;the other is neutral.We can conclude that
A)all field lines leaving the positively charged pith ball end on the neutral pith ball.
B)some of the field lines leaving the positively charged pith ball end on the neutral pith ball.
C)none of the field lines leaving the positively charged pith ball end on the neutral pith ball.
D)positive charge is transferred along the field lines until both balls have equal charges.
E)positive charge is transferred along the field lines until both balls hang along vertical lines.

Question

Two identical pith balls supported by insulating threads hang side by side and close together,as shown below.  One is positively charged;the other is neutral.We can conclude that
A)all field lines leaving the positively charged pith ball end on the neutral pith ball. 
B)some of the field lines leaving the positively charged pith ball end on the neutral pith ball. 
C)none of the field lines leaving the positively charged pith ball end on the neutral pith ball. 
D)positive charge is transferred along the field lines until both balls have equal charges. 
E)positive charge is transferred along the field lines until both balls hang along vertical lines.

Quizplus · Accepted Answer

When the positively charged ball is brought close to the neutral ball, the excess positive charges on the positively charged ball repel the electrons on the neutral ball, causing a redistribution of charges. This results in a temporary induced dipole in the neutral ball, with the side closer to the positively charged ball being negatively charged and the side away from it being positively charged. As a result, some of the field lines leaving the positively charged ball end on the neutral ball, attracting it towards the positively charged ball. However, once the balls are close enough, the insulating threads prevent further transfer of charge, and the charges on the balls reach an equilibrium state. In this state, the charges on the balls are such that the electric field they produce cancels out each other in the region between them, and both balls hang along vertical lines.

Two Identical Pith Balls Supported by Insulating Threads Hang Side