This section addresses the distribution of water on Earth. It covers the dynamic processes of the hydrological cycle, the morphological features of the ocean floor, and the chemical/physical properties of marine environments.
With reference to Ocean Mean Temperature (OMT), which of the following statements is/are correct?
OMT is measured up to a depth of 26oC isotherm which is 129 meters in the south-western Indian Ocean during January-March.
OMT collected during January-March can be used in assessing whether the amount of rainfall in monsoon will be less or more than a certain long-term mean.
Select the correct answer using the code given below:
Correct Answer:
(B) 2 only
The 26oC isotherm is noticed at depths varying between 50-100 metres. During January-March, the mean 26oC isotherm in the South western Indian Ocean is at a depth of 59 metres. Ocean mean temperature (OMT) compared to sea surface temperature (SST) better predicts whether the total amount of rainfall that India will receives during monsoon season will be less or more than the long term mean of 887.5 mm.
Ques: 2
Which one of the following seas is the deepest?
Correct Answer:
(A) South China Sea
The South China Sea is part of Pacific Ocean, encompassing an area from Karimata and Malacca strait to the strait of Taiwan. It is 5016 mt. deep while Bering Sea is 4773 mt. deep, Mediterranean Sea is 4632 mt. deep and Japan Sea is 3742 mt. deep. Thus, deepest sea in the given option is South China Sea.
Ques: 3
The surface of the earth covered with water is approximately?
Correct Answer:
(C) Two-thirds
Around 30% of the total surface Area of the Earth is land (about 148300000 sq. km) and 70% part (about 361800000 sq. km) is covered by water ( including all oceans, seas, rivers and other water bodies). Hence, the surface of earth covered with water is approximately two-thirds of the total surface area.
Ques: 4
Datum line :
Correct Answer:
(A) Is a horizontal line to the sea level from where heights and depths are measured
The Datum line is a horizontal line from where all the elevations and depths are measured.
The most predominant datums types today are tidal datums and geodetic datums. Tidal datums are determined by averaging the level of water at a tide gage over time. Some simple examples of these are Mean Sea Level (MSL), Mean Low Water (MLW) and Mean Higher High Water (MHHW).
Ques: 5
The largest part of our hydrosphere is –
Correct Answer:
(C) Pacific ocean
The area of given oceans is as follows – Pacific Ocean (165.2 million square kilometre), Atlantic Ocean (106.4 million square kilometre), Indian Ocean (73.6 million square kilometre), Antarctica Ocean (2.6-18.8 million square kilometre). Hence largest part of our hydrosphere is the Pacific Ocean.
Ques: 6
The tension of gravitational water in the ground is –
Correct Answer:
(A) Below 1/3 atmosphere
Gravitational water occupies the larger soil pores (macro-pores) and moves down readily under the force of gravity. Gravitational water under the surface of soil remains in a state of zero or less than 1/3 of the atmosphere.
Ques: 7
Consider the following statements:
On the planet Earth, the fresh water available for use amounts to about less than 1% of the total water found.
Of the total freshwater found on the planet Earth, 95% is bound up in polar ice caps and glaciers.
Which of the statements given above is/are correct?
Correct Answer:
(A) 1 only
97% of the total water available on Earth is salt water found in Ocean. Out of the remaining 3% Fresh water, 2.4% is in the form of glaciers and polar ice, which is unusable for us. So, in this way total available fresh water to use is less than 1% of the total water available on earth. Out of total amount of fresh water (3%), 68.7% is found in the form of glaciers and polar ice, 30.1% in the form of underground water, 0.3% in the form of surface water and remaining 0.9% is found in other forms. Hence only statement (1) is correct.
Ques: 8
Which one is the most extensive part of the oceanic floor?
Correct Answer:
(D)
Deep Sea Plains
A most extensive part of the oceanic floor is 'Deep sea plain'. Characterized by flat and rolling submarine plain it is the most extensive relief zone of the ocean basins. These deep-sea plains having the depth of 3000 m to 6000 meters cover more than 76% percent of the total area of the Ocean Basins.