Temerpature of a furnace is more than 500^(@)C. Discuss a method of measuring the temperature of the furnace with the help of a thermometer graduated up to 100^(@)C.

Temerpature of a furnace is more than 500^(@)C. Discuss a method of me

1.	Temerpature of a furnace is more than 500^(@)C. Discuss a method of measuring the temperature of the furnace with the help of a thermometer graduated up to 100^(@)C.
Answer» SOLUTION :Let the temperature of the FURNACE `=t^(@)C`. A small METLA piece of mass m and specific heat s is put into the furnace. Obvioulsy the melting point of the metal should be greater than the temperature of the furnace so that it does not melt. Now, water of mass M is taken is a vessel of water equivalent W and its temperature is recorded. Let the temperature be `t_(1)^(@)C(ltlt 100^(@)C)`. Now the HOT metal piece is dropped in the water. As a result a small quantity OFWATER is vapourised which is negligible. After a while, when the metla piece and water reach thermal equili - brium, the final temperature is measured by the thermometer. If that temperature is `t_(2).^(@)C`, heat lost by the metal piece = `ms(t-t_(2))` and heat hained by the vessel and water `=(W+M)s_(w)(t_(2)-t_(1))`, where `s_(w)` is the specific heat of water. From calorimetric principle, `ms(t-t_(2))=(W+M)s_(w)(t_(2)-t_(1))` Value of t can be calculated from this equation if values of all the other quantities are known. Thus, measuring temperatures `t_(1) and t_(2)` with the help of a thermometer graduated up to `100^(@)C`, a much greater temperature t can be determined.