Question

Question 5.
A point charge Q is placed at point O as shown in the figure. Is the potential
difference VA - VB positive, negative or zero, if Q is
(i) positive
(ii) negative?
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Answer 1

Explanation:

the potential due to a point charge decreases with increases of distance. so in case 1 ( VA-VB) is positive...

in case 2 ( VA- VB) is negative....

Answer 2

Answer:

VA - VB = 0

This happens when q>0 as Potential difference between two points in an electrostatic field is the amount of work done against the field in moving a unit +ve charge from one point to other.

=> VA > VB

And hence Q is positive.