Charges of ?q and +2q are fixed in place, with a distance of 5.25 m between them
ID: 2150293 • Letter: C
Question
Charges of ?q and +2q are fixed in place, with a distance of 5.25 m between them. A dashed line is drawn through the negative charge, perpendicular to the line between the charges. On the dashed line, at a distance L from the negative charge, there is at least one spot where the total potential is zero. Find L.
Explanation / Answer
Potential = KQ/R
At the point of Zero potential
- 9 x 109 x q / L + 9 x 109 x 2q / L2 + 5.252 = 0
9 x 109 x q / L = 9 x 109 x 2q / L2 + 5.252
On solving,
3L2 = 5.252
L = 3.03 m