IB Physics SL B 2 6 Mean Solar Intensity Questions

Practise IB Physics SL B.2.6 by deriving global mean solar intensity and using albedo to model absorbed energy and planetary temperature.

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Derive global mean intensity as S/4 by comparing Earth's intercepting disc with its full surface.
Combine S/4 with albedo and emissivity to calculate absorbed intensity or equilibrium temperature.

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Study B.2.6—Mean solar intensity conceptsOpen the corresponding Concept lesson for explanations, examples and exam connections.

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The diagram shows a simplified energy-balance model for the Earth surface–atmosphere system.

Figure for Question IB Physics SL B 2 6 Mean Solar Intensity Questions question 1 — IB Physics SL

The following data are given:

\begin{aligned} \text { Average albedo of Earth } & =0.30 \\ \text { Average global temperature of the surface } & =288 \mathrm{~K} \\ \text { Average Earth-Sun distance } & =1.5 \times 10^{11} \mathrm{~m} \end{aligned}

Show that the average global intensity of radiation absorbed by the surface is about $240 \mathrm{Wm}^{-2}$ .

Average incoming intensity $=\frac{S}{4}$ « $=340 \mathrm{~W} \mathrm{~m}^{-2}$ »

Absorbed intensity $=(1-0.30) \times 340$ or $238 \mathrm{~W} \mathrm{~m}^{-2}$

The steps in the calculation must be
shown.

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IB Physics SL B 2 6 Mean Solar Intensity Questions question 1