In a room where temperature is 0 ∘ C , two objects A and B are kept. A is a black body at a temperature of 27 3 ∘ C and B is an object of emissivity 0.3 and temperature of 54 6 ∘ C . Both bodies have

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In a room where temperature is 0 ∘ C , two objects A and B are kept. A is a black body at a temperature of 27 3 ∘ C and B is an object of emissivity 0.3 and temperature of 54 6 ∘ C . Both bodies have same area and mass. If specific heat capacity of A is half that of B , the ratio of initial rates of colling of A and B will be :-

TestHub · Accepted Answer

Rate of coiling = dt dT ​ = ms e σ A ​ [ T b 4 ​ − T c 4 ​ ] ​ [ dt dT ​ ] A ​ = m × s A ​ 1 × σ A 2 ​ [ ( 2 T ) 4 − ( T ) 4 ] ​ [ dt dT ​ ] B ​ = m × s B ​ 0.3 × σ A ​ [ ( 3 T ) 4 − ( T ) 4 ] ​ [ dt dT ​ ] B ​ [ dt dT ​ ] A ​ ​ = 2 s A ​ 0.3 × 80 ​ 15/ s A ​ ​ = 3 × 80 300 ​ = 4 5 ​ ​

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