Question

how pyrometer works to measure high temperature of graphite furnace?

Answer 1

An optical pyrometer calibrated for an ideal black body radiation gives too low a value for temperature of a red-hot iron piece kept in the open. Black body radiation equation is given by

this equation is also known as Stefan's law of radiation .

Where,

E = Energy radiation

T = Temperature of optical pyrometer

T.not= Temperature of open space

σ = Stefan's constant

from above formula, it is clearly shown that, an increase in the temperature of open space reduces the radiation energy. When the same piece of iron is placed in a furnace, the radiation energy, E = σT⁴