It takes 100 J of work to move 2.2 C of charge from the negative plate to the positive plate
of a parallel plate capacitor.
What voltage difference exists between the
plates?
Answer in units of V.

when insulating materials rub against each other, they may become electrically charged . electrons , which are negatively charged, may be 'rubbed off' one material and on to the other. the material that gains electrons becomes negatively charged. the material that loses electrons is left with a positive charge.