GATE 2022 AR — Architecture – Question 55
A blackbody radiant heating panel has area 5 m² and surface temperature 35°C. A 1 m² surface at 20°C is 1 m away. With Stefan–Boltzmann constant 5.6703×10⁻⁸ W/m²/K⁴, find the panel’s radiant heat emission in W, to two decimals.
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Show answer and explanation
Correct answer: 2550.00 to 2560.00
Explanation
The question asks gross emission, so use E=σAT⁴ with emissivity 1. Temperature is 35+273.15=308.15 K. Thus E=5.6703×10⁻⁸×5×308.15⁴≈2556.38 W. The other surface’s temperature, area and separation would matter to an exchange calculation with an appropriate view factor, not this gross emission.