Most ozone gas (about 90%) is located in the atmospheric layer of
- A.ionosphere
- B.troposphere
- C.stratosphere
- D.mesosphere
Correct answer
Explanation
The correct answer is C, stratosphere. About 90% of the atmosphere's ozone lies in the stratosphere, forming the ozone layer.
The stratosphere extends from the top of the troposphere, about 8 km at the poles and 18 km at the equator, up to about 50 km. The ozone is concentrated mostly between 15 and 35 km. Ozone (O₃) absorbs most of the Sun's harmful ultraviolet-B and ultraviolet-C rays, protecting life on Earth, and this absorption warms the layer, which is why temperature rises with height in the stratosphere. Ozone is measured in Dobson units, and the "ozone hole" over Antarctica was caused by CFCs, controlled by the Montreal Protocol of 1987.
A is wrong because the ionosphere, at about 80–400 km, is known for charged particles that reflect radio waves, not for ozone. B is wrong because the troposphere holds only about 10% of ozone, where it is a harmful pollutant. D is wrong because the mesosphere, above 50 km, has very little ozone and is the coldest layer.
Exam tip: Ozone layer = stratosphere (15–35 km), about 90% of ozone; Montreal Protocol 1987; ozone measured in Dobson units.
Practice Questions
View allWhich one of the following is applicable to collision-coalescence process of precipitation?
- A.Clouds which do not extend beyond the freezing level
- B.Clouds which extend beyond the freezing level
- C.All types of clouds
- D.Cirrocumulus cloud
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Collision-coalescence is the way rain forms in warm clouds, whose tops stay below the level where water freezes. In such clouds all droplets are liquid.
Read the full explanation →Identify the type of drainage pattern on the basis of the given characteristics :
1. It represents the most common pattern of streams and their tributaries
2. It occurs in areas of uniform rock type and regular slope
3. A map, or aerial photograph, shows a pattern like the veins on a leaf— smaller streams join the main stream at an acute angle
Select the correct answer.
- A.Dendritic
- B.Radial
- C.Trellis
- D.Centripetal
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A pattern that looks like the branches of a tree or the veins of a leaf, formed on uniform rock with a regular slope, is dendritic.
Read the full explanation →The Research Design and Standards Organization is the R&D wing of which one of the following organizations ?
- A.Bhabha Atomic Research Centre
- B.Indian Space Research Organization
- C.Indian Railways
- D.Defence Research and Development Organization
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The Research Design and Standards Organisation (RDSO) is the sole research and development wing of the Ministry of Railways. RDSO is headquartered at Lucknow.
Read the full explanation →Which one of the following Indian States has recorded negative growth population as per Census 2011?
- A.Manipur
- B.Mizoram
- C.Tripura
- D.Nagaland
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Nagaland was the only Indian state whose population fell between 2001 and 2011; its decadal growth rate in Census 2011 was about −0.6 per cent.
Read the full explanation →Piecing together the puzzle of geologic time to create and analyze historical maps of the Earth is known as
- A.paleoclimatology
- B.paleogeomorphology
- C.paleolithology
- D.paleogeography
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Paleogeography is the study of the Earth's geography in the geological past, and its main product is a set of maps showing where continents, oceans, mountains and shorelines lay at different times.
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