Question

while calculating electric field should we include the sign of the charge in the formula?

Answer 1

yep

Answer 2

the electric field has a positive direction associated with it

Answer 3

That direction is the direction that positively charged particle will be forced,
an negatively charged particle will move in the opposite direction,
the magnitude of the force relative to the charge will be the same

Answer 4

If you want just the magnitude of the force, then no sign is needed.

Answer 5

However, if you are using the vector form of the electric field equation, the convention is to consider the signs of the charges.

Answer 6

If you want just the magnitude of the electric field in a point located at a distance r from the central charge Q:
\[E=k\frac{|Q|}{r^2}\]
where |Q| is the magnitude of the charge, with no sign.
If you want the electric field vector in a point located at a distance r from the central charge Q:
\[\vec{E}=k\frac{Q}{r^2}\hat{r}\]
where Q is the charge with its sign and \[\hat{r}\]is the unit vector that points from the charge Q to the point in question.

Answer 7

i can not imagine a situation where the sign of the charge is not important enough to include in the equation

Answer 8

In my opinion, the only situation where the sign is not important is if you want just the magnitude (the absolute value) of the electric field in a given point in space.

Answer 9

yeah that is what is is by definition