The heat budget of the earth

Answer: A, heat balance. Earth receives short-wave energy from the Sun and sends energy back to space mainly as long-wave infrared radiation. Carbon dioxide absorbs some of this outgoing infrared radiation and re-emits energy in different directions, including toward the surface. When atmospheric carbon dioxide increases, the rate at which heat escapes can change, disturbing Earth’s energy balance and contributing to warming until a new balance is reached. Option B is wrong because rotation is mainly related to Earth’s angular momentum and gravitational interactions. Option C is wrong because ocean depth is controlled by basin shape, tectonics, erosion, and sea-level processes. Option D is wrong because rocks do not change colour immediately merely because carbon dioxide increases. Memory cue: CO₂ traps outgoing heat; it does not control Earth’s spin or instantly recolour rocks.

The correct answer is A. Stratospheric ozone absorbs much of the Sun’s harmful ultraviolet radiation, helping protect life from excessive UV exposure. Carbon dioxide has a different role: it is a greenhouse gas that absorbs some outgoing infrared radiation and therefore contributes to Earth’s heat balance. Neither is a main respiratory gas or a dust particle.

Earth receives mainly shortwave solar radiation and then emits energy back as longwave terrestrial radiation. Greenhouse gases such as carbon dioxide, methane and water vapour absorb part of this outgoing longwave radiation and re-emit energy, including downward energy, thereby influencing the heat balance and warming the lower atmosphere. Thus option D is correct; the other choices confuse reflection, pressure or an impossible lunar energy source.

Correct answer: A. Earth’s surface receives energy from the Sun and sends energy back mainly as infrared radiation. Water vapour and carbon dioxide absorb some of this outgoing infrared energy and re-emit it, so they are important to the atmospheric heat balance and greenhouse effect. Studying them together helps a learner understand why atmospheric composition influences temperature. They are not identical: water vapour changes rapidly with weather, while carbon dioxide is more persistent and is strongly linked to the carbon cycle. B is therefore wrong because neither is absolutely permanent in the same sense. C is wrong because both occur in the atmosphere, not only the lithosphere. D is wrong because tides are mainly related to gravitational effects of the Moon and Sun.

Direct answer: C is correct. Atmospheric gases help control Earth’s temperature, radiation balance and chemical environment. If greenhouse gases increase substantially, more outgoing infrared energy can be retained, disturbing the heat balance and contributing to climate change. Other gases and pollutants can harm human and animal health, reduce visibility, damage plants and alter ecological relationships. The effects are connected but not identical: greenhouse gases mainly influence climate, while pollutants may directly affect air quality and living organisms. A is wrong because gas imbalance does not make oceans invisible. B is wrong because it cannot instantly change the length of a day. D is physically impossible in this context. Memory cue: atmospheric imbalance can disturb heat, health and habitats.

Direct answer: A is correct. Sunlight mainly arrives as shorter-wave radiation and warms Earth’s surface. The warmed surface then emits infrared, or longwave, radiation upward. Water vapour and carbon dioxide absorb some wavelengths of this outgoing radiation and re-emit energy in different directions. Part of the re-emitted energy travels back downward, slowing the loss of heat to space and influencing surface and lower-atmosphere temperature. This is the basic greenhouse effect; it does not mean that all radiation is trapped permanently. B is wrong because these gases do not merely form dust. C is wrong because tides are mainly associated with gravitational effects of the Moon and Sun. D is wrong because these gases do not change Earth’s internal structure. Memory cue: “The surface sends heat upward; greenhouse gases absorb and re-emit part of it.”

Answer: A. Water vapour is not only the raw material for clouds and rainfall; it is also an important part of Earth’s energy system. Water vapour absorbs some outgoing infrared radiation, so it contributes to the natural greenhouse effect and influences temperature. During evaporation, energy is taken from the surface and stored as latent heat in the water vapour. When vapour condenses to form clouds or rain, this latent heat is released into the surrounding air. These linked processes transport energy and help regulate atmospheric temperature while also producing precipitation. A is correct because it includes both the greenhouse role and latent-heat role. B is incorrect because water vapour does not only form stones. C is incorrect because evaporation and condensation involve energy transfer. D is incorrect because atmospheric water vapour mainly comes from evaporation and transpiration, not from a star. Memory cue: evaporation stores heat; condensation releases it.

A is correct. Greenhouse gases such as carbon dioxide and methane affect how much outgoing infrared energy the atmosphere absorbs and re-emits. Aerosols can also affect radiation and clouds, with effects that depend on their type and location. Comparing changes in atmospheric composition with measured trends in temperature, rainfall and radiation helps scientists assess climate change; no single measurement alone establishes the full evidence.

The correct answer is A. Earth’s warmed surface emits energy as longwave (infrared) radiation. Carbon dioxide absorbs some of this outgoing radiation and re-emits energy, contributing to the greenhouse effect and influencing Earth’s heat balance. Its climatic importance therefore depends on its radiative properties, not just its abundance.

Correct answer: A. Earth’s radiative balance compares incoming solar energy with outgoing energy, especially the longwave infrared radiation emitted by Earth’s surface and atmosphere. Carbon dioxide is a greenhouse gas that absorbs some outgoing infrared wavelengths and re-emits energy in various directions. This directly affects how readily terrestrial heat escapes to space. Argon and neon are noble gases with little direct absorption of the relevant infrared radiation under ordinary atmospheric conditions. Sea-salt particles can scatter or absorb some radiation and may influence clouds, but they are particles rather than the best gas answer in this question. A does not mean CO₂ is the only substance involved; water vapour, clouds, and other gases also matter. It is the most direct and suitable choice among the options. Memory cue: radiative balance and greenhouse gases are linked through infrared radiation.

The correct answer is A. Aerosols are tiny particles or droplets suspended in air. They can scatter or reflect some incoming sunlight, changing how much solar energy reaches the surface and thus affecting temperatures over short periods. Some aerosols can also absorb radiation, but the other options describe effects aerosols do not cause.

A is correct. Ozone in the stratosphere absorbs much of the Sun’s harmful ultraviolet radiation, reducing the amount that reaches Earth’s surface. The absorbed energy warms the surrounding air, so temperature generally increases with altitude through much of the stratosphere. Most ordinary storms and heavy rainfall occur in the troposphere, not the stratosphere.

Option A is correct. The atmosphere is relatively transparent to much incoming shortwave solar radiation, while Earth’s surface absorbs that energy and emits longwave infrared radiation. The lower troposphere is therefore heated mainly from below, and convection and conduction transfer heat upward. Ozone production, direct ion escape, and zero surface pressure do not explain the tropospheric temperature pattern.

Correct answer: A. In the mesosphere, temperature generally decreases as altitude increases. One important reason is that the concentration of ozone and other gases able to absorb radiation is relatively small compared with the stratosphere. Less absorption means less radiative heating at greater heights, so the temperature tends to fall upward. Option A expresses this idea accurately, although the atmosphere’s complete energy balance is more detailed than one single factor. Option B is wrong because terrestrial radiation is strongest nearer Earth’s surface and is not maximum in the mesosphere. Option C is wrong because ordinary rain clouds occur mainly in the troposphere, not the mesosphere. Option D is wrong because the greatest ozone concentration is associated with the stratosphere. The key comparison is: stratosphere warms upward because ozone absorption is important; mesosphere cools upward because that absorption becomes much weaker. Memory cue: less absorbing gas aloft generally means less heating aloft.

In the common heat budget about thirty five units return and sixty five units are absorbed. Use the hundred unit model as the exam base.

The atmosphere adds fourteen and thirty four units and sends forty eight units back to space. Remember forty eight units as atmospheric output.

Some longwave energy from the surface goes directly to space and more is absorbed by the atmosphere. Remember the seventeen and thirty four relation.

Thirty five reflection seventeen direct terrestrial and forty eight atmospheric output make hundred. In exams check the total outgoing sum.

In the usual account about twenty seven units are reflected by clouds and about two by surface. Treat clouds as the major reflector.

Energy returned by atmospheric scattering is part of total reflected energy. Link scattering with returned energy in exams.

The surface emits longwave energy and the atmosphere absorbs much of it. Understand the surface atmosphere link through longwave energy.

More cloud reflection means less energy reaches the surface. In exams connect more clouds with lower daytime heating.

Greenhouse gases trap and re radiate longwave energy emitted by Earth. Link them with terrestrial energy in exams.

More clouds or absorbing gases can reduce direct escape of longwave energy. In exams link direct outgoing energy with atmospheric transparency.

In energy surplus received energy is greater than lost energy. Link surplus with warming in exams.