IB Physics HL B.2.6 Mean solar intensity Question Bank

Practise IB Physics HL B.2.6 by combining S/4 geometry, albedo, atmospheric transmission and emissivity in planetary energy-balance models.

Exam points

Apply S/4, albedo and atmospheric transmission to calculate planetary surface or global absorbed intensity.
Use energy balance and emissivity to determine equilibrium temperatures for Earth, Moon or Titan.

[Maximum number: 2]

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

Figure for Question B.2.6—Mean solar intensity question 1 — IB Physics HL

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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B.2.6—Mean solar intensity question 1