Question

In contrast to net electric field, when you calculate the voltage (electrical potential) at a point in space relative to 0 V (defined as the electric potential halfway between two equal and opposite charges) – whether it’s due to the presence of one or more large charges – it is critical for you to include the sign of the Q’s that are creating the electric field. Why?

Answer 1

Electrical potential is a saclar quantity, hence net potential at a point due to two or more charges is calculated as scalar summation (algebric summation). We use minus sign for negative charge. But this is not the case of electric field, since electric field is a vector quantity and net field is added as a vector summation which include direction of field rather minus sign for negative charge.

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