Earth wire is used in the electric instruments as: [PYQ 2024]

An earth wire is used as a safety measure in electrical instruments to protect users from electric shock. It connects the metal casing of an appliance to the ground, providing a low-resistance path for excess current to flow to the earth in case of a fault, such as a live wire touching the casing. This prevents the appliance's metal body from becoming live and causing a shock if a person touches it.