Free B.2 Greenhouse effect questions for IB Physics (SL & HL), part of B The particulate nature of matter. Each question has the answer and the marking points an examiner would look for.
Generate a full B.2 Greenhouse Effect worksheet →All B The particulate nature of matter questionsThe solar constant is 1360 W m−2 and the albedo of a planet is 0.25.
What is the mean intensity of solar radiation absorbed over the whole surface of the planet?
Answer: B
Which statements about the greenhouse effect are correct?
I. Greenhouse gases re-emit infrared radiation in all directions, including back to the surface.
II. Increasing the albedo of the surface increases the mean surface temperature.
III. Greenhouse gases absorb infrared radiation emitted by the Earth’s surface.
Answer: B
The solar constant is 1360 W m−2 and the Earth’s albedo is 0.30.
Show that the mean intensity incident per square metre of the Earth’s surface is 340 W m−2.
Calculate the mean intensity absorbed.
Calculate the equilibrium surface temperature assuming the Earth is a black body.
The actual mean surface temperature is 288 K. Determine the effective emissivity of the Earth.
Explain how greenhouse gases cause the surface temperature to be higher.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | 340 W m−2 1360/4 = 340 W m−2 ✓ | 1 |
| (b) | 238 W m−2 0.70 × 340 = 238 W m−2 ✓ | 1 |
| (c) | 255 K 238 = σT4 ✓ T = 255 K ✓ | 2 |
| (d) | 0.61 e = 238/(5.67 × 10−8 × 2884) ✓ = 0.61 ✓ | 2 |
| (e) | absorb and re-emit IR greenhouse gases absorb infrared radiated by the surface ✓ and re-emit it in all directions, some back towards the surface ✓ | 2 |
The Earth’s surface has an average temperature of 288 K and an emissivity of 0.95.
Calculate the intensity radiated by the surface.
Explain how greenhouse gases cause the surface temperature to be higher than it would otherwise be.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | 370 W m−2 eσT4 ✓ 370 W m−2 ✓ | 2 |
| (b) | absorb IR, re-radiate in all directions greenhouse gases absorb infrared emitted by the surface ✓ molecules vibrate at matching frequencies ✓ re-radiate in all directions, some back to the surface ✓ | 3 |
The solar constant at Mars is 590 W m−2 and its albedo is 0.25. Assume the surface has an emissivity of 1.00.
State what is meant by the solar constant.
Show that the mean intensity absorbed by the surface is about 110 W m−2.
Determine the equilibrium surface temperature.
Explain how an atmosphere containing greenhouse gases increases the surface temperature.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | intensity of solar radiation at the planet’s mean distance intensity / power per unit area of solar radiation incident at the planet’s mean distance from the star ✓ | 1 |
| (b) | 111 W m−2 S/4 because of rotation and the ratio of disc area to surface area ✓ × (1 − 0.25) = 111 W m−2 ✓ | 2 |
| (c) | 210 K I = eσT4 ✓ T = 210 K ✓ | 2 |
| (d) | absorb IR, re-emit in all directions surface emits infrared radiation ✓ greenhouse gases absorb it as the frequency matches molecular vibration (resonance) ✓ re-emit in all directions, some back to the surface ✓ | 3 |
This question is about climate feedback.
Explain how melting ice can increase global warming.
Name two greenhouse gases.
Explain, in molecular terms, how greenhouse gases absorb infrared radiation.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | albedo falls, positive feedback ice has a higher albedo than water or land ✓ when ice melts less radiation is reflected ✓ more is absorbed, causing more warming and more melting (positive feedback) ✓ | 3 |
| (b) | CO₂, CH₄ any two of CO2, CH4, H2O, N2O ✓ | 1 |
| (c) | resonance of bonds infrared frequencies match natural frequencies of vibration of the molecular bonds ✓ resonance causes the energy to be absorbed ✓ | 2 |
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Meet Riyaz →Original IB-style practice questions written for mentorriyaz.in. These are not IB past paper questions, and this site is not affiliated with or endorsed by the International Baccalaureate Organization. Updated 2026-11-04. Paper generator · mentorriyaz.in