One very small uniformly charged plastic ball is located directly above another such charge in a test tube as shown in the figure.The balls are in equilibrium a distance d apart.If the charge on each ball is doubled,the distance between the balls in the test tube would become
A) d.
B) 2d.
C) 4d.
D) 8d.

Question

One very small uniformly charged plastic ball is located directly above another such charge in a test tube as shown in the figure.The balls are in equilibrium a distance d apart.If the charge on each ball is doubled,the distance between the balls in the test tube would become 
A) d. 
B) 2d. 
C) 4d. 
D) 8d.

Quizplus · Accepted Answer

The distance between two charged objects is inversely proportional to the square root of their charges. Thus, if we double the charge on each ball, the distance between them will be reduced by a factor of √2. Therefore, the new distance between the balls will be √2d, which is approximately 1.414d or 2d. Hence, the best choice is B.

One Very Small Uniformly Charged Plastic Ball Is Located Directly