Question 872: Thermodynamics & KTG

Question

Heat energy is incident on the surface at the rate of X J/min . If '$$a$$' and '$$r$$' represent coefficient of absorption and reflection respectively then the heat energy transmitted by the surface in '$$t$$' minutes is

Accepted Answer

$$	ext { We know } \quad 1=\mathrm{a}+\mathrm{r}+\mathrm{t}_{\mathrm{r}}$$
$$\Rightarrow \mathrm{t}_{\mathrm{r}}=1-(\mathrm{a}+\mathrm{r})$$
$$	ext { Heat transmitted }=\mathrm{t}_{\mathrm{r}} 	imes 	ext { time }$$
$$	herefore \quad \mathrm{Q}=\mathrm{X} 	imes(1-\mathrm{a}+\mathrm{r}) 	imes \mathrm{t} \ldots\left(	ext { Substituting for } \mathrm{t}_{\mathrm{r}}ight)$$
$$\mathrm{Q}=\mathrm{X}(1-\mathrm{a}+\mathrm{r}) 	imes \mathrm{t}$$

Answer

$$(a+r) x t$$

Answer

$$\frac{(\mathrm{a}+\mathrm{r})}{\mathrm{xt}}$$

Answer

$$-(a+r) x t$$

Answer

$$\frac{\mathrm{xt}}{(\mathrm{a}+\mathrm{r})}$$

Thermodynamics & KTG

Heat energy is incident on the surface at the rate of X J/min . If '$a' and 'r' represent coefficient of absorption and reflection respectively then the heat energy transmitted by the surface in 't$' minutes is

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