Question

there are two kinds of charges how do we know this?​

Answer 1

There are two kinds of charge in nature and they are Positive and negative. Glass rod and silk cloth rubbing experiment shows the exchange of charge.

Answer 2

Answer:

There are two types of electric charge: positive charge and negative charge. If the same amounts of negative and positive charge are found in an object, there is no net charge and the object is electrically neutral. ... Positive charge is carried by the protons in material and negative charge by electrons.

Hope it helps you..