I understand that potential is for a point/space and potential energy is dependent on field which applies only when we have more than 1 charge.
But please consider this system of charges. Three point charges shown here lie at the vertices of an equilateral triangle. The question in the book is to find the electrostatic potential energy of this system of three charges - whether it would be positive or negative?
Now, what is the real significance of this potential energy of the 'system'? As I imagine, if I bring in a +ve charge from infinity to near the +ve charge in this system, it is going to get repelled. and vice-versa if I bring in a +ve charge from infinity to near the -ve charge in this system.
So, even if I calculate a value of potential energy for this 'system' (ex: -2 Joules), what does this value really signify?