IB Physics Quiz: Apply Greenhouse Effect
20 questions · exam conditions
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Apply Greenhouse EffectQuestion 1 of 20

Earth's atmosphere is composed primarily of nitrogen (N₂) and oxygen (O₂). Why are these gases not significant contributors to the greenhouse effect?

They are monatomic gases and therefore cannot vibrate to absorb infrared radiation.
Their molecular bonds are too strong to be broken by the energy of infrared photons.
They are symmetric diatomic molecules whose vibrations do not create a changing electric dipole moment.
They exist at altitudes too high in the atmosphere to effectively trap heat radiating from the Earth's surface.
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IB Physics Quiz

IB Physics Quiz: Apply Greenhouse Effect

Practice Apply Greenhouse Effect in IB Physics with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

What this quiz covers

This quiz focuses on Apply Greenhouse Effect, giving you a quick way to practice the rules, question types, and explanations that matter most for IB Physics.

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

All questions

Question 1

Earth's atmosphere is composed primarily of nitrogen (N₂) and oxygen (O₂). Why are these gases not significant contributors to the greenhouse effect?

  1. They are monatomic gases and therefore cannot vibrate to absorb infrared radiation.
  2. Their molecular bonds are too strong to be broken by the energy of infrared photons.
  3. They are symmetric diatomic molecules whose vibrations do not create a changing electric dipole moment. (correct answer)
  4. They exist at altitudes too high in the atmosphere to effectively trap heat radiating from the Earth's surface.
Explanation: For a molecule to absorb infrared radiation, it must have a vibrational mode that causes a change in its electric dipole moment. Symmetric diatomic molecules like N₂ and O₂ have no permanent dipole moment, and when they vibrate, their symmetry is preserved, so no oscillating dipole moment is created. Therefore, they cannot interact with and absorb the electromagnetic field of an IR photon. Choice A is factually incorrect; they are diatomic. Choice B misunderstands the mechanism; absorption doesn't break bonds. Choice D is incorrect; these gases are well-mixed throughout the troposphere where the greenhouse effect is strongest.

Question 2

Greenhouse gases like water vapour (H₂O) and methane (CH₄) strongly absorb infrared radiation but are largely transparent to incoming visible light. What is the primary physical reason for this difference?

  1. The energy of infrared photons corresponds to allowed transitions between molecular vibrational states, while visible light photons have too much energy for these transitions. (correct answer)
  2. The atmosphere's density is significantly lower at altitudes where visible light is most intense, which reduces the probability of absorption.
  3. Visible light is reflected by these molecules rather than absorbed, while infrared radiation is absorbed rather than reflected.
  4. The electric field component of infrared radiation oscillates at a frequency that matches the molecules' natural resonant frequencies, unlike that of visible light.
Explanation: Molecular energy levels (electronic, vibrational, rotational) are quantized. Infrared photons have energies that match the gaps between vibrational energy levels in greenhouse gas molecules. Visible light photons have much higher energies, corresponding to gaps between electronic energy levels. Since these molecules don't have electronic transitions in the visible range, they are transparent to visible light but absorb IR at their specific vibrational frequencies. Choices B and C are incorrect descriptions of the physical processes. Choice D is close but less precise than A; 'vibrational states' is the key concept from the syllabus.

Question 3

The thawing of Arctic permafrost is observed to release large quantities of methane, a potent greenhouse gas. This leads to further atmospheric warming, which in turn accelerates the thawing of permafrost. How is this cycle best described?

  1. A negative feedback loop, because the released methane will eventually be chemically removed from the atmosphere.
  2. A positive feedback loop, because an initial warming triggers a process that causes additional warming. (correct answer)
  3. A primary climate forcing, because it is an external factor that directly alters the planet's energy balance.
  4. An example of molecular resonance, where the permafrost thaw frequency matches the absorption frequency of methane.
Explanation: This is a classic example of a positive feedback loop in the climate system. The initial change (warming) causes a secondary effect (permafrost thaw and methane release) that amplifies the initial change (more warming). A negative feedback loop would counteract the initial change. Choice A is incorrect because while methane has a finite lifetime, its immediate effect is to amplify warming. Choice C is incorrect; the initial warming is the forcing, while the permafrost response is a feedback. Choice D completely misuses the term 'resonance' in this context.

Question 4

A planet's surface is in thermal equilibrium. It absorbs energy from its star and also from its own greenhouse atmosphere (back-radiation). If the concentration of greenhouse gases in its atmosphere increases, what is the immediate effect on the energy balance at the surface and the eventual effect on the surface temperature?

  1. The back-radiation from the atmosphere increases, causing the surface to warm to a new, higher equilibrium temperature. (correct answer)
  2. The back-radiation from the atmosphere decreases, causing the surface to cool to a new, lower equilibrium temperature.
  3. The energy absorbed from the star increases, while back-radiation stays the same, leading to a higher surface temperature.
  4. The back-radiation increases, but the surface temperature remains the same due to an increase in surface emissivity.
Explanation: An increased concentration of greenhouse gases means the atmosphere becomes more effective at absorbing outgoing longwave radiation from the surface and re-radiating it. A significant fraction of this re-radiation is directed back down towards the surface ('back-radiation'). This increases the total energy input to the surface. To restore equilibrium, the surface must radiate more energy, which, according to the Stefan-Boltzmann law (P ∝ T⁴), requires its temperature to rise. Choice B has the effect reversed. Choice C incorrectly identifies the source of the extra energy. Choice D assumes an unsubstantiated change in emissivity.

Question 5

For a planet with a thick greenhouse atmosphere, radiation escapes to space not from the surface, but from an effective 'emission altitude'. How does an increase in greenhouse gas concentration affect this emission altitude and the planet's energy balance?

  1. It lowers the emission altitude to a warmer layer, increasing outgoing radiation and causing cooling.
  2. It raises the emission altitude to a higher, colder layer, reducing outgoing radiation and causing warming. (correct answer)
  3. It does not affect the emission altitude, but increases the temperature at that altitude to radiate more energy.
  4. It makes the entire atmosphere transparent to IR, so the emission altitude effectively becomes the surface.
Explanation: Adding more greenhouse gases makes the atmosphere more opaque to infrared radiation. This means that for radiation to escape to space, it must originate from higher up in the atmosphere where the air is thinner. In the troposphere, temperature decreases with altitude. Therefore, the new, higher emission altitude is at a colder temperature. According to the Stefan-Boltzmann law, a colder body radiates less energy. This reduction in outgoing radiation creates a positive energy imbalance (incoming > outgoing), which causes the entire climate system to warm until a new equilibrium is reached. A and D are the opposite of what occurs. C is incorrect because the altitude shift is the key mechanism.

Question 6

The absorption of a photon of infrared radiation by a molecule of methane (CH₄) in the atmosphere causes the molecule to transition to a higher energy state. This absorbed energy corresponds primarily to an increase in which type of molecular energy?

  1. Electronic energy
  2. Nuclear binding energy
  3. Translational kinetic energy
  4. Vibrational energy (correct answer)
Explanation: Molecular energy is quantized into electronic, vibrational, and rotational levels. The energy of infrared photons corresponds to the energy differences between the quantized vibrational states of molecules like methane. When an IR photon is absorbed, the molecule transitions to a higher vibrational state, meaning its atoms vibrate with greater amplitude. Electronic transitions (A) require higher-energy photons (visible or UV). Translational kinetic energy (C) is not quantized in this way. Nuclear binding energy (D) involves processes at vastly higher energies.

Question 7

A massive volcanic eruption injects large quantities of both carbon dioxide (a greenhouse gas) and sulfate aerosols into the stratosphere. What is the most likely net effect on the average global surface temperature in the one to two years following the eruption?

  1. A net warming, because the injected CO₂ immediately enhances the long-term greenhouse effect.
  2. A net cooling, because the aerosols increase the planetary albedo by reflecting solar radiation. (correct answer)
  3. No significant net change, as the warming from CO₂ and cooling from aerosols are of similar magnitude.
  4. A net warming, because the sulfate aerosols also absorb outgoing infrared radiation, adding to the greenhouse effect.
Explanation: While volcanic eruptions do release CO₂, the short-term (1-3 years) climate impact is dominated by the injection of sulfate aerosols into the stratosphere. These aerosols form a haze that reflects incoming solar radiation, increasing the planet's albedo. This reflection of shortwave radiation causes a net cooling effect that is more immediate and pronounced than the warming effect from the added CO₂. Therefore, a temporary global cooling is the most likely outcome. A and D are incorrect. C is incorrect because the two effects are not typically balanced in the short term.

Question 8

Two planets, X and Y, are identical except for their surface properties. Planet X has a surface with an average emissivity of 0.9, while Planet Y has a surface with an average emissivity of 0.6. Both have identical, significant greenhouse atmospheres. How will their average surface temperatures likely compare?

  1. Planet Y will be warmer because its lower emissivity means it traps heat more effectively at the surface.
  2. Planet X will be warmer because its higher emissivity allows it to absorb back-radiation from the atmosphere more effectively.
  3. Both planets will have the same temperature as emissivity only affects emission, and the greenhouse effect determines temperature.
  4. Planet Y will be warmer because with lower emissivity, its surface must reach a higher temperature to radiate away the energy it absorbs. (correct answer)
Explanation: A planet's surface must radiate away the energy it absorbs from its star and from its atmosphere to maintain equilibrium. The power radiated is given by the Stefan-Boltzmann law, P = εσAT⁴. For a given amount of absorbed power P, a surface with a lower emissivity (ε) must have a higher temperature (T) to radiate that same amount of power. Therefore, Planet Y, with the lower emissivity, will have a higher surface temperature. Choice B is flawed because absorptivity equals emissivity, but the key is the temperature required for radiative balance. Choice A uses correct but imprecise reasoning. Choice C is incorrect as emissivity is fundamental to achieving thermal balance.

Question 9

A planet is in a state of radiative equilibrium. A large quantity of a long-lived greenhouse gas is then suddenly added to its atmosphere. Which statement describes the immediate and subsequent changes to the planet's energy budget?

  1. Outgoing radiation immediately exceeds incoming radiation, causing the planet to cool towards a new, colder equilibrium.
  2. The system remains in equilibrium, as the atmosphere instantly adjusts its temperature to radiate the excess energy away.
  3. The planetary albedo immediately increases, reflecting more solar energy and causing a period of rapid cooling.
  4. Incoming radiation immediately exceeds outgoing radiation, causing the planet to warm until a new, hotter equilibrium is reached. (correct answer)
Explanation: The addition of a greenhouse gas makes the atmosphere more opaque to outgoing infrared radiation, immediately reducing the rate at which energy leaves the planet. The incoming solar radiation remains unchanged. This creates an energy imbalance where energy in > energy out. This net gain of energy causes the planet system (oceans, land, atmosphere) to warm. As the system warms, it emits more radiation (Stefan-Boltzmann law). The warming continues until the outgoing radiation increases enough to once again balance the incoming radiation, establishing a new equilibrium at a higher temperature. Choice A has the imbalance reversed. Choice C confuses the effect with that of aerosols. Choice D is incorrect; the adjustment process is not instantaneous and requires a change in temperature.

Question 10

The 'atmospheric window' is a range of infrared wavelengths (around 8–14 μm) where there is little atmospheric absorption, allowing thermal radiation to escape directly to space. How does the enhanced greenhouse effect impact this window?

  1. The atmospheric window widens as temperatures rise, allowing more heat to escape as a negative feedback.
  2. Anthropogenic gases like CFCs, as well as increased CH₄, absorb radiation within this window, effectively narrowing it. (correct answer)
  3. The window corresponds to wavelengths emitted by greenhouse gases, not the Earth's surface, so it is unaffected.
  4. The enhanced greenhouse effect only involves increased absorption at wavelengths outside the window, primarily by CO₂.
Explanation: The atmospheric window is a crucial pathway for the Earth to cool. While major greenhouse gases like H₂O and CO₂ have absorption bands outside this window, other gases, particularly methane (CH₄), nitrous oxide (N₂O), and synthetic gases like chlorofluorocarbons (CFCs), have significant absorption bands within this window. Increasing the concentration of these gases 'dirties' the window, blocking a previously open escape route for infrared radiation and thus enhancing the overall greenhouse effect. Choice A is incorrect. Choice C incorrectly describes the window. Choice D is incorrect as narrowing the window is a key part of the enhanced effect.

Question 11

A planet with a stable greenhouse gas atmosphere experiences a large-scale event that permanently increases its average surface albedo. What is the long-term consequence for the planet's average surface temperature?

  1. The temperature will increase because more radiation is reflected back into the greenhouse gas layer, increasing atmospheric absorption.
  2. The temperature will decrease because a smaller fraction of the incident solar radiation is absorbed by the planet's surface. (correct answer)
  3. The temperature will remain unchanged because the greenhouse gas concentration, which determines the warming, has not changed.
  4. The temperature will decrease because the higher albedo increases the emissivity of the surface, allowing it to cool more efficiently.
Explanation: Albedo is the fraction of incident solar radiation that is reflected back to space. If the albedo increases, the planet as a whole absorbs less energy from its star. According to the principle of energy balance, for the planet to reach a new thermal equilibrium, it must radiate less energy. Based on the Stefan-Boltzmann law (P = σAT⁴), a lower power output corresponds to a lower equilibrium temperature. Therefore, the planet's average temperature will decrease. Choice A misunderstands reflection. Choice C incorrectly assumes the greenhouse effect is independent of the initial energy input to the surface. Choice D incorrectly links albedo and emissivity; they are distinct properties.

Question 12

An exoplanet orbiting a red dwarf star has a dense CO₂ atmosphere. The planet is tidally locked, with one side permanently facing the star and the other in perpetual darkness. How would the greenhouse effect differ between the day and night sides, and what would be the primary mechanism?

  1. The day side shows stronger greenhouse effect due to higher thermal emission requiring more atmospheric absorption to maintain surface temperature
  2. The greenhouse effect is negligible on both sides due to the extreme temperature difference preventing atmospheric circulation
  3. Both sides show identical greenhouse effects since atmospheric composition and density remain uniform across the planet
  4. The night side shows stronger greenhouse effect because atmospheric re-radiation becomes the primary heat source in absence of stellar input (correct answer)
Explanation: When analyzing atmospheric effects on tidally locked exoplanets, you need to consider how the greenhouse effect operates differently when stellar radiation is present versus absent. The greenhouse effect works by trapping outgoing thermal radiation from a planet's surface. On the day side of this tidally locked planet, the surface receives continuous stellar heating, so the greenhouse effect supplements but doesn't dominate the energy budget. However, on the night side, atmospheric re-radiation becomes the sole mechanism maintaining surface temperature above what it would be without an atmosphere. Option D correctly identifies that the night side experiences a stronger greenhouse effect because atmospheric absorption and re-emission of thermal radiation is the primary—and only—heat source keeping the surface warm. The dense CO₂ atmosphere absorbs outgoing infrared radiation and re-radiates it back to the surface, creating a significant warming effect. Option A incorrectly suggests the day side has stronger greenhouse effects due to higher thermal emissions, but higher surface temperature actually means the greenhouse effect contributes proportionally less to the total energy budget. Option B wrongly claims the greenhouse effect is negligible on both sides—atmospheric density and composition don't disappear due to temperature differences. Option C assumes uniform effects despite fundamentally different energy sources on each side. For IB Physics exams, remember that greenhouse effect strength isn't just about atmospheric composition—it's about the relative importance of atmospheric heating compared to other energy sources. When direct stellar heating is absent, atmospheric effects become proportionally more significant.

Question 13

A climate research team is comparing the greenhouse effects of two different atmospheric gases on a model planet. Both gases absorb infrared radiation but have different molecular properties affecting their greenhouse potential.

Gas P has a lifetime of 10 years and strongly absorbs radiation at 12 μm wavelength. Gas Q has a lifetime of 100 years and moderately absorbs radiation at 8 μm wavelength. If equal masses of both gases are released into the atmosphere, which factor would be most important in determining their relative contributions to long-term planetary warming?

  1. Gas P will dominate due to its superior absorption coefficient at specific infrared wavelengths
  2. Gas Q will dominate because its extended atmospheric lifetime allows greater cumulative warming effect (correct answer)
  3. The absorption wavelength determines impact, with 8 μm radiation being more effective for warming
  4. Both gases will contribute equally since identical masses were released into the atmosphere
Explanation: For long-term warming, atmospheric lifetime is crucial because it determines how long the gas remains active. Gas Q's 100-year lifetime means it will continue absorbing infrared radiation 10 times longer than Gas P, leading to greater cumulative warming despite moderate absorption strength. A focuses only on instantaneous absorption. C oversimplifies wavelength effects without considering atmospheric windows. D ignores the fundamental differences in molecular behavior.

Question 14

A space mission measures the outgoing longwave radiation from a planet at the top of its atmosphere and finds it to be 180 W m−2180 \ \text{W m}^{-2}. The planet receives 720 W m−2720 \ \text{W m}^{-2} of solar radiation and has an albedo of 0.4. If this planet achieves thermal equilibrium, what can be concluded about its energy balance?

  1. The planet is in perfect thermal equilibrium since outgoing radiation balances absorbed solar radiation
  2. The planet is losing energy and will cool down because outgoing radiation is less than absorbed radiation
  3. The planet is gaining energy and will warm up because absorbed radiation exceeds outgoing radiation (correct answer)
  4. The energy balance cannot be determined without knowing the planet's greenhouse gas concentration and surface temperature
Explanation: Absorbed solar radiation = 720×(1−0.4)=432 W m−2720 \times (1 - 0.4) = 432 \ \text{W m}^{-2}. Since outgoing longwave radiation is only 180 W m−2180 \ \text{W m}^{-2}, there is a net energy gain of 432−180=252 W m−2432 - 180 = 252 \ \text{W m}^{-2}. The planet will warm until outgoing radiation increases to match absorbed radiation. A incorrectly assumes equilibrium exists. B reverses the energy flow direction. D is wrong because the energy balance can be calculated from the given radiation values.

Question 15

A planet's atmosphere has reached a state where further increases in CO₂ concentration produce diminishing returns in surface warming. This occurs because the main CO₂ absorption bands are becoming saturated. If engineers propose releasing a different greenhouse gas that absorbs in currently transparent atmospheric windows, which principle would best predict the effectiveness of this approach?

  1. The new gas will be highly effective because it exploits previously unused portions of the infrared spectrum for atmospheric heating (correct answer)
  2. The new gas will show moderate effectiveness but less than expected due to overlapping absorption with existing atmospheric constituents
  3. The new gas will be ineffective because greenhouse saturation is a planetary property independent of specific absorption wavelengths
  4. The effectiveness depends primarily on the molecular weight and atmospheric lifetime rather than the absorption wavelength characteristics
Explanation: When existing greenhouse gases have saturated their absorption bands, a new gas absorbing in transparent atmospheric windows (8-12 μm region) would be highly effective because it captures previously escaping infrared radiation. This exploits unused spectral regions for greenhouse warming. B underestimates the impact of using transparent windows. C incorrectly treats saturation as wavelength-independent. D focuses on secondary factors rather than the key spectral absorption principle.

Question 16

A climate scientist is studying two planets with identical solar irradiance and surface compositions but different atmospheric compositions. Planet A has a thin atmosphere with low greenhouse gas concentration, while Planet B has a thick atmosphere with high greenhouse gas concentration.

If both planets suddenly experience a 10% increase in solar irradiance, which statement best describes the expected temperature response and the underlying physical mechanism?

  1. Planet A will show a larger temperature increase because its thin atmosphere provides less thermal inertia to resist changes
  2. Planet B will show a larger temperature increase due to enhanced greenhouse effect amplifying the additional incoming radiation (correct answer)
  3. Both planets will show identical temperature increases since they receive the same percentage increase in solar input
  4. Planet A will show a larger temperature increase because the greenhouse effect on Planet B will saturate at higher temperatures
Explanation: Planet B's thick atmosphere with high greenhouse gas concentration will trap more of the additional thermal radiation from the warmed surface, amplifying the temperature increase. The greenhouse effect scales with both incoming radiation and atmospheric opacity. A is wrong because thermal inertia affects response time, not final equilibrium temperature. C ignores the different atmospheric greenhouse effects. D incorrectly suggests greenhouse saturation at these temperature ranges.

Question 17

Which statement best distinguishes the enhanced greenhouse effect from the natural greenhouse effect?

  1. The natural effect is caused only by water vapour and CO₂, while the enhanced effect is caused only by methane and N₂O.
  2. The enhanced effect involves the atmospheric absorption of incoming ultraviolet radiation, which is not part of the natural effect.
  3. The enhanced effect refers to the additional warming caused by anthropogenic emissions of greenhouse gases above their natural levels. (correct answer)
  4. The natural effect maintains a stable climate equilibrium, while the enhanced effect leads to an unstable climate with irreversible tipping points.
Explanation: The natural greenhouse effect is the baseline warming caused by naturally occurring greenhouse gases. The 'enhanced' greenhouse effect refers specifically to the amplification of this natural effect due to human activities (anthropogenic emissions) increasing the concentration of these gases (like CO₂, CH₄, N₂O) and introducing new ones (like CFCs). Choice A is incorrect as CO₂ and H₂O are major contributors to both effects. Choice B is incorrect; both effects concern infrared radiation, not UV (which is related to the ozone layer). Choice D is too absolute; the natural climate also experiences shifts and contains feedback loops.

Question 18

Which statement most accurately describes the flow of radiative energy in the greenhouse effect?

  1. The atmosphere absorbs most of the incoming shortwave solar radiation and transmits most of the outgoing longwave thermal radiation.
  2. The atmosphere is largely transparent to incoming shortwave solar radiation and largely opaque to outgoing longwave thermal radiation. (correct answer)
  3. The atmosphere absorbs a large fraction of radiation at all wavelengths, both incoming and outgoing, acting like an insulating blanket.
  4. The atmosphere reflects most incoming shortwave solar radiation and absorbs the longwave radiation that is reflected from the surface.
Explanation: The fundamental mechanism of the greenhouse effect relies on the differential absorption properties of the atmosphere. It allows a large fraction of the high-energy, short-wavelength radiation from the Sun (mostly visible light) to pass through to the surface. However, it absorbs a significant fraction of the lower-energy, long-wavelength thermal radiation (infrared) emitted by the warmed Earth surface. This trapped energy leads to warming. Choice A has the properties reversed. Choice C is an oversimplification. Choice D incorrectly describes reflection and absorption processes.

Question 19

Carbon dioxide (CO₂) is a linear triatomic molecule and a key greenhouse gas. Which property related to its molecular structure is essential for its ability to absorb infrared radiation?

  1. Its atoms are held together by strong double covalent bonds.
  2. It is heavier than the N₂ and O₂ molecules that dominate the atmosphere.
  3. Its bending and asymmetric stretching vibrations create a temporary, oscillating electric dipole moment. (correct answer)
  4. Its linear shape allows it to resonate easily with the straight paths of infrared photons.
Explanation: For a molecule to be infrared-active, it must undergo a change in its electric dipole moment during a vibration. Although CO₂ is symmetric and has no permanent dipole moment when at rest, certain vibrational modes (like bending and asymmetric stretching) distort its symmetry. This distortion creates a temporary, oscillating dipole moment that can interact with the electric field of an incoming IR photon, allowing the photon to be absorbed. Choice A and B are true but are not the reason for IR absorption. Choice D is a physically inaccurate description.

Question 20

The warming inside a glass greenhouse is often used as an analogy for the Earth's greenhouse effect. What is a key physical difference in the dominant warming mechanism?

  1. A glass greenhouse traps infrared radiation due to the properties of glass, while the atmosphere traps ultraviolet radiation.
  2. The glass of a greenhouse warms the interior air primarily through conduction, while the atmosphere is warmed directly by absorbing solar radiation.
  3. A glass greenhouse primarily works by physically trapping warm air and preventing convection, while the atmospheric effect is a radiative process. (correct answer)
  4. The warming in a glass greenhouse is a localized, temporary effect, while the atmospheric greenhouse effect is a global, permanent phenomenon.
Explanation: The analogy is somewhat misleading. While glass is transparent to visible light and partially opaque to infrared (a radiative effect), the primary reason a physical greenhouse gets hot is that the glass roof and walls prevent the air inside, which has been heated by the sun-warmed surfaces, from rising and mixing with cooler air outside. It suppresses heat loss by convection. The atmospheric greenhouse effect, in contrast, is fundamentally a radiative phenomenon based on the absorption and re-radiation of infrared energy by gases. Choice A has the radiation type wrong. B is not the dominant difference. D describes the scale, not the mechanism.