All Free Everyday Science MCQs with Answers

651. The thermosphere extends from an altitude of ________ to the base of ________ at ________?

• 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. Atmospheric boundaries are gradual and can vary slightly by reference source.

652. _________ is the layer wherein most meteors are incinerated before reaching the surface.

• 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. The ionosphere is a region of ionised gas that overlaps upper atmospheric layers, not the main meteor-burning layer.

653. The mesosphere ranges from ________ to _________?

• 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. It lies above the stratosphere and below the thermosphere.

654. Stratosphere is the atmospheric layer that absorbs most of __________ that Earth receives from the Sun.

• 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. Infrared radiation is not the main radiation absorbed by this layer.

655. _________ is the atmospheric layer that absorbs most of the ultraviolet radiation that Earth receives from the Sun.

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

Explanation: The stratosphere absorbs most solar ultraviolet radiation because it contains the ozone layer. The other layers do not contain the main concentration of atmospheric ozone responsible for this absorption.

656. Stratosphere is present at an altitude between _________.

• A. 15 km and 35 km
• B. 17 km and 35 km
• C. 18 km and 35 km
• D. 19 km and 35 km

Explanation: Many basic texts place the stratosphere approximately between 15 and 35 km in this simplified classification, although broader scientific definitions extend it from roughly 12 to 50 km. The question follows the narrower textbook range represented by option a.

657. _________ extends from the top of the troposphere to the bottom of the mesosphere.

• A. Thermosphere
• B. Ionosphere
• C. Stratosphere
• D. None of the above

Explanation: The stratosphere begins at the top of the troposphere and ends at the stratopause, below the mesosphere. The thermosphere lies much higher, while the ionosphere overlaps several atmospheric layers.

658. ____________ contains 75-80 % of the mass of the atmosphere.

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

Explanation: The troposphere contains most atmospheric mass because gravity concentrates air near Earth’s surface. It also holds nearly all atmospheric water vapour and clouds.

659. Troposphere extends from planetary surface to bottom of __________?

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

Explanation: The troposphere extends upward from Earth’s surface to the tropopause, which is the bottom boundary of the stratosphere. Thus, the next atmospheric layer is the stratosphere.

660. __________ is the lowest layer of the atmosphere.

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

Explanation: The troposphere is the lowest atmospheric layer and is where humans live and most weather occurs. Above it lies the stratosphere.