Question

describe the construction,working and usefulness of a dry cell

Answer 1

A dry cell consists of a zinc container whose base acts as the negative electrode. The carbon rod placed at the centre with a brass cap acts as the positive electrode. This is surrounded by a mixture of manganese dioxide and charcoal in a muslin bag. The electrolyte uses is a moist paste of ammonium chloride. The outer body (excluding the base) of the zinc container is insulated with cardboard. 

When the dry cell is connected in a circuit comprising a bulb, current flows in the circuit due to the chemical reaction that takes place in the cell. This makes the bulb glow. The dry cell is a primary cell and it cannot be recharged.