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प्रश्न
Calculate the amount of heat radiated per second by a body of surface area 12 cm2 kept in thermal equilibrium in a room at temperature 20°C. The emissivity of the surface = 0.80 and σ = 6.0 × 10−8 W m−2 K−4.
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उत्तर
Given:
Area of the body, A = 12 × 10−4 m2 Temperature of the body, T = (273 + 20) = 293 K
Emissivity, e = 0.80
Rate of emission of heat, R = AeσT4
R = 12 × 10−4 × 0.80 × 6.0 × 10−8 × (293)4
R = 0.42 J (approximately)
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