Home / IBDP Physics- B.2 Greenhouse effect- IB Style Questions For SL Paper 2

IBDP Physics- B.2 Greenhouse effect- IB Style Questions For SL Paper 2 -FA 2025

IBDP Physics SL Paper 2 -FA 2025- All Chapters

Question

A satellite powered by solar cells directed towards the Sun is in a polar orbit about the Earth.
The satellite is orbiting the Earth at a distance of \(6.6 \times 10^{6}\,\text{m}\) from the centre of the Earth.
The satellite carries an experiment that measures the peak wavelength emitted by different objects. The Sun emits radiation with a peak wavelength \(\lambda_S = 509\,\text{nm}\). The peak wavelength \(\lambda_E\) of the radiation emitted by the Earth is \(10.1\,\mu\text{m}\).
(a) Determine the orbital period for the satellite.
Mass of Earth \(= 6.0 \times 10^{24}\,\text{kg}\) [3]
(b)(i) Determine the mean temperature of the Earth. [2]
(b)(ii) Suggest how the difference between \(\lambda_S\) and \(\lambda_E\) helps to account for the greenhouse effect. [3]
(c) Not all scientists agree that global warming is caused by the activities of humans. Outline how scientists try to ensure agreement on a scientific issue. [1]

Most-appropriate topic codes (IB Physics):

• Topic D.1: Gravitational fields — part (a)
• Topic B.2: Thermal radiation and the greenhouse effect — parts (b)(i) and (b)(ii)
• Nature of science: Scientific collaboration and peer review — part (c)
▶️ Answer/Explanation
Detailed solution

(a)
For a circular orbit, \[ \frac{mv^2}{r}=\frac{GMm}{r^2} \] which gives \[ T^2=\frac{4\pi^2 r^3}{GM} \] Substituting \(r=6.6\times10^{6}\,\text{m}\) and \(M=6.0\times10^{24}\,\text{kg}\), \[ T \approx 5.3\times10^{3}\,\text{s} \]

(b)(i)
Using Wien’s displacement law, \[ \lambda_{\max}T=2.90\times10^{-3} \] \[ T=\frac{2.90\times10^{-3}}{10.1\times10^{-6}}\approx2.87\times10^{2}\,\text{K} \] Mean temperature of the Earth \(\approx 287\,\text{K}\) (about \(14^\circ\text{C}\)).

(b)(ii)
Radiation from the Sun has a much shorter wavelength and passes largely through the atmosphere. The Earth emits longer-wavelength infrared radiation, which is absorbed by greenhouse gases. This radiation is re-emitted in all directions, including back towards the Earth, reducing energy loss and increasing the surface temperature.

(c)
Scientists use peer review, repeat experiments, publish methods and results in detail, and collaborate internationally so findings can be checked and verified.

More B.2 Greenhouse effect SL Paper 2 Questions..
Scroll to Top