IB Physics SL B.2.5 Solar constant S

Practise defining the solar constant correctly and explaining why its quoted value is approximate rather than perfectly fixed.

Syllabus
First assessment 2025
Objective
—
Level
SL

Exam points

  • state the solar constant as the solar radiation intensity at Earth's mean orbital distance from the Sun
  • explain why the value is approximate by linking it to changing solar output and Earth's elliptical orbit

B.2.5—Solar constant S question 1

[Maximum number: 1]

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

Figure for Question B.2.5—Solar constant S question 1 — IB Physics SL

The following data are given:

 Average albedo of Earth =0.30 Average global temperature of the surface =288 K Average Earth-Sun distance =1.5×1011 m\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}

State what is meant by the solar constant.

All question bank results loaded