In hot wire instrument, the sensing wire is made of
Right Answer is:
In hotwire instrument, the sensing wire is made of Platinum-iridium.
Hotwire instruments utilize the principle of expansion of wire, heat due to the current being measured, passing through the wire.
It consists of a hot wire of platinum-iridium because it can withstand high temperatures of about 300°C without being oxidized), and about 0.2 mm in diameter.