Ans. CONDUCTORS
The materials which allow electricity to pass through them are called conductors.
Conductors have excess of free electrons which are not held strongly with any particular atom of the metals. These free electrons move randomly in all directions inside metals. When we apply external electric field, these electrons can easily move in a specific direction. This movement of free electrons in a particular direction under the influence of an external electric field causes the flow of current in
the metal wire.
INSULATORS
The materials which do not allow electricity to pass through them are called
insulators.
All metals, like; silver and copper are conductors.
The electrons in insulators, like rubber, are not free to move. They are tightly bound inside true atoms. Hence, current cannot flow through an insulator because there are no free electrons for the flow of current. Insulators have very large value of resistance. Insulators can be easily charged by friction and the induced charge remains static on their surface. Other examples of insulators are glass, wood, plastic, fur, silk, etc.