Free Environment and Atmosphere MCQs with Answers

• A. 1 gram
• B. 10 grams
• C. 1 kg
• D. 10 kg

Explanation: Sea-water salinity is conventionally expressed as the mass of dissolved salts in one kilogram of seawater, commonly about 35 grams per…

• A. Oxygen - Carbon dioxide
• B. Carbon dioxide - Oxygen
• C. Oxygen - Carbon monoxide
• D. None of theseCarbon monoxide - Oxygen

Explanation: In darkness, photosynthesis stops but respiration continues, so plants generally take in oxygen and release carbon dioxide.

• A. Oxygen
• B. Hydrogen
• C. Carbon Dioxide
• D. Silicon

Explanation: Oxygen is the most abundant element in Earth's crust by mass, largely because it is combined with silicon and metals in widespread rocks…

• A. Methane
• B. Hydrogen
• C. Nitrous oxide
• D. Ozone

Explanation: Hydrogen is not normally classified as a greenhouse gas because it does not significantly absorb outgoing infrared radiation.

• A. Sedimentary rock
• B. Schist rock
• C. Igneous rock
• D. Metamorphic rock

Explanation: Igneous rocks form when molten magma or lava cools and solidifies. Sedimentary rocks form from deposited material, while metamorphic rocks…

• A. Increasing
• B. Decreasing
• C. Remains same
• D. First decreases then increases

Explanation: Atmospheric pressure decreases with altitude because there is less air above exerting weight on a given area.

• A. Increased oxygen level
• B. Decreases greenhouse gases
• C. Increased greenhouse gases
• D. Increased ethane level

Explanation: Burning coal, oil and gas releases carbon dioxide and other gases that increase the atmospheric greenhouse effect.

• A. Average height (H)
• B. Scale height (H)
• C. Mean height (H)
• D. Standard height (H)

Explanation: The scale height is the vertical distance over which atmospheric pressure falls to 1/e, or about 36.8%, of its original value.

• A. Electrosphere
• B. Magnetosphere
• C. Spectrosphere
• D. Echosphere

Explanation: The outer exosphere merges gradually with space and interacts with Earth's magnetosphere, the region controlled by the planet's magnetic…

• A. Troposphere
• B. Stratosphere
• C. Mesosphere
• D. Ionosphere

Explanation: The stratosphere contains the concentrated ozone layer, generally about 15–35 km above Earth's surface.

• A. Troposphere
• B. Stratosphere
• C. Mesosphere
• D. Thermosphere

Explanation: Most weather occurs in the troposphere because it contains most atmospheric water vapour and is heated from Earth's surface, producing…

• A. Mass of vertical column of atmospheric gases
• B. Mass of horizontal column of atmospheric gases
• C. Weight of vertical column of atmospheric gases
• D. Mass of vertical and weight of horizontal of atmospheric gases

Explanation: Atmospheric pressure is caused by the weight of the vertical column of air above a surface area.

• A. Troposphere
• B. Mesosphere
• C. Exosphere
• D. Stratosphere

Explanation: The exosphere is the outermost atmospheric layer, beginning roughly 690 to 1,000 km above Earth and extending thousands of kilometres into…

• A. Its density is lesser at short distances from planetary surface in morning and further decreases as ionosphere rises at night-time, thereby allowing a greater range of radio frequencies to travel greater distances
• B. Its density is greater at short distances from tplanetary surface in daytime and decreases as ionosphere rises at night-time, thereby allowing a greater range of radio frequencies to travel greater distances
• C. Its density is greater at long distances from planetary surface in daytime and further increases as ionosphere rises at night-time, thereby allowing a greater range of radio frequencies to travel greater distances
• D. None of the above

Explanation: The ionosphere is denser in its lower regions during daytime because solar radiation produces more ions, while reduced ionisation at night…

• A. Pressure of the planetary body
• B. Gravity of the planetary body
• C. Charge of the planetary body
• D. Heat of the planetary body

Explanation: Gravity pulls atmospheric gases toward a planet and prevents most of them from escaping into space.

• A. 75 km, Mesosphere, 670 km
• B. 80 km, Ionosphere, 680 km
• C. 85 km, Exosphere, 690 km
• D. 90 km, Ozone Layer , 690 km

Explanation: In the simplified atmospheric model used here, the thermosphere begins near 85 km and extends to about 690 km, where the exosphere begins.

• A. Troposphere
• B. Stratosphere
• C. Mesosphere
• D. Ionosphere

Explanation: Most meteors burn up in the mesosphere because air resistance heats them intensely as they enter this layer.

• A. 46 km to 85 km
• B. 48 km to 85 km
• C. 50 km to 85 km
• D. 52 km to 85 km

Explanation: The mesosphere is conventionally described as extending from about 50 km to 85 km above Earth's surface.

• A. Infrared radiation
• B. Ultraviolet radiation
• C. Ozone layer
• D. Radio waves

Explanation: The stratosphere contains the ozone layer, which absorbs most incoming ultraviolet radiation, especially harmful UV-B and UV-C.

• A. Troposphere
• B. Stratosphere
• C. Mesosphere
• D. Ionosphere

Explanation: The stratosphere absorbs most solar ultraviolet radiation because it contains the ozone layer.