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MediumQ. No. what-is-the-total-radiation-pyrometer-based-on
What is the total radiation pyrometer based on?
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AWien's law
BNewton's cooling law
CSnell's law
DStefan's law
Correct Answer: Stefan's lawYour Answer: D
The Total Radiation Pyrometer collects all radiation from a hot body to measure temperature. Option A is wrong — Wien's law relates peak wavelength to temperature and is used by Optical Pyrometers, not Total Radiation Pyrometers. Option B is wrong — Newton's cooling law describes rate of heat loss by convection and has no role in pyrometry. Option C is wrong — Snell's law is about refraction of light at boundaries and is unrelated to temperature measurement. Option D is CORRECT — Total Radiation Pyrometer is based on Stefan-Boltzmann law: E = σT⁴. It collects all wavelengths of radiation from the hot body and focuses them on a thermocouple or bolometer. By measuring total energy received, temperature is calculated using Stefan's law. Range: 800°C to 3000°C. This is slightly wider than Optical Pyrometer (800°C to 2700°C). Stefan constant σ = 5.67×10⁻⁸ W/m²K⁴. Temperature must be in Kelvin for this formula.
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Heat is a form of energy that transfers between objects or systems due to a temperature difference, moving from a hotter body to a cooler one until thermal equilibrium is reached.
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