Describe the construction, working and usefulness of a dry cell, with the help of a diagram.
Construction of dry cell
The dry cell consists of following components:
Outer metal covering: The metal covering is made up of zinc metal and is whitish in appearance. It acts as a negative terminal of the cell.
Electrolyte: Inside the Zinc metal, there is the electrolyte filled between two layers. Electrolyte is a wet pulp of Zinc chloride (ZnCl2) and Ammonium chloride (NH4Cl). It is the charge carrier of electricity as it contains negatively charged and positively charged ions.
Metal rod: There is a graphite rod at the centre of the cell. It is surrounded by paste of Manganese dioxide (MnO2). It acts as the positive terminal of the cell.
Working of dry cell: Chemical reactions take place between the electrolyte, zinc container and graphide rod. Because of this, electric charge is produced on the two terminals of the cell and electric current flows in the circuit.
Usefulness of dry cell: They are handy and portable. The life of dry cell is longer than cells using liquid electrolyte. Dry cells can be use in torch, T.V. or A.C remote controls, toys, etc.