Question

Explain conservation of charge giving two examples.

Answer 1

Hint: The law of conservation of charge says that the net charge of an isolated system will always remain constant.

Complete step by step solution:
Mainly there are two types of charges positive and negative charges. To understand about this property, we must know the basic structure of atoms. Atoms consist of three basic particles: protons, electrons, and neutrons. The nucleus (centre) of the atom contains the protons (positively charged) and the neutrons (no charge). The outermost regions of the atom are called electron shells and contain the electrons (negatively charged).
So, any change in the charge of an atom is due to changes in its electron count. Neutron atom does not mean that it does not contain any positive and negative charges. It also contains both positive and negative charges, but the number of positive charges equal to the number of negative charges. If a neutral atom gains electrons, then it will become negatively charged, If a neutral atom loses electrons, then it becomes positively charged.
Let us look into a few examples to understand the conservation of charges in depth.

Ex. 1: When a glass rod is rubbed with silk cloth both will get charged when rubbed with each other.
Let us consider a glass rod and silk cloth both are neutral at the beginning. Now take the glass rod and gently rub it with silk cloth. Now few electrons from glass rod will get transferred to silk cloth, hence in glass rod the number of positive charges is more than negative charges; hence it is said to be positively charged. On the other side silk cloth gains the electrons which were lost by glass rod, then the number of negative charges is more than positive charges. Hence majority charge carriers are negative charges in case of silk rods. Glass rod will get positively charged and silk cloth will get negatively charged by the same amount. i.e. If 2 electrons are lost by a glass rod, the same 2 electrons are gained by silk cloth. Here we note that no extra charges are created, both will get charge only due to gaining and losing electrons.

E.x. 2: A glass and fur material both will get charged when rubbed with each other.
Let us consider a glass and fur material both are neutral at the beginning. Now take the glass rod and gently rub it with fur material. Now few electrons from fur material will get transferred to glass rod, hence in fur material the number of positive charges is more than negative charges; hence it is said to be positively charged. On the other side glass rod gains the electrons which were lost by fur material, then the number of negative charges is more than positive charges. Hence majority charge carriers are negative charges in case of glass rod. Hence glass rods will get negatively charged, fur material will get positively charged. i.e. If 2 electrons will get transferred from fur material to glass rod the same 2 electrons gained by glass rod. Here we note that no extra charges are created, both will get charge only due to gaining and losing electrons.
“Charge can neither be created nor be destroyed but can be transferred from one body to another”. This is known as the law of conservation of charges.

Note: When an atom is said to be positive charge, it does not mean that it contains only positive charge. It also contains negative charges also; we must note that it means the majority charge carriers are positive charges. i.e. The number of positive charges is more than negative charges.