Question

If you rub any two things against each other what changes do you find in them

Answer 1

When two different bodies made of different material are rubbed against each other, electrons are transferred from the material with lower work function to the material with higher work function. For instance, when a glass rod is rubbed with a silk cloth, some electrons are transferred from glass rod to silk. The glass rod develops a positive charge due to deficiency of electrons while the silk cloth develops an equal negative charge due to excess of electrons.