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A person has 1.6 m² of skin at 33 °C and sits in a room whose walls are at 18 °C.

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A person has $1.6\ \text{m}^2$ of skin at $33\ ^\circ\text{C}$ and sits in a room whose walls are at $18\ ^\circ\text{C}$ . The skin's emissivity is $0.97$ . Find the power the skin gives out, and the net power lost by radiation. ( $\sigma = 5.67 \times 10^{-8}\ \text{W m}^{-2}\text{K}^{-4}$ .)

Need a reminder? The key ideaShow

Radiation: $P = e\sigma AT^4$ , net $e\sigma A(T^4 - T_0^4)$ , with $\sigma = 5.67 \times 10^{-8}\ \text{W m}^{-2}\text{K}^{-4}$ and $T$ in kelvin. Wien: $\lambda_mT = 2.90 \times 10^{-3}\ \text{m K}$ .

The worked solution

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