How can we identify that a body is negatively or positively charged ?
Answers
Explanation:
In order to tell the sign of an object charge, you need another object with a known positive or negative charge. If you rub a piece of glass with silk, it will have a positive charge (by convention). ... If your object is repelled by the glass, then it has the same charge as the glass (positive).
Well positive and negative charge are convention. What we call positive charge we could've called negative charge, and what we call negative charge we could've called positive charge. There are devices that detect charges, they use charged objects. Imagine I have a negatively charged ball. Remember that we could've called that ball positively charged, but the whole of the scientific community decided to call it negatively charged. If I bring a charge ball next to it, if it repels that charged ball is what we call negative. If it attracts then that charged ball is what we call positive. This convention goes down all the way to particles. In the end, someone just decided to say that electrons are negatively charged, and everything followed after. If you rub a piece of glass with silk, it will have a positive charge (by convention). If you rub a piece of amber with fur, it will have a negative charge (also by convention). Use whatever you have handy. Let's say you use a piece of glass rubbed with silk. If your object is repelled by the glass, then it has the same charge as the glass (positive). Otherwise, your object has a negative charge.