Solution : b)

Unattempted. Explanation :-

Statement 1 is incorrect. The actual amount of water vapour present in the atmosphere is known as the absolute humidity.

The percentage of moisture present in the atmosphere as compared to its full capacity at a given temperature is known as the relative humidity. With the change of air temperature, the capacity to retain moisture increases or decreases and the relative humidity is also affected. It is greater over the oceans and least over the continents. Hence, statement 2 is correct.

Water vapour present in the air is known as humidity. It is expressed quantitatively in different ways. It is the weight of water vapour per unit volume of air and is expressed in terms of grams per cubic metre.

Source) FUNDAMENTALS OF PHYSICAL GEOGRAPHY; Chapter 11; page number 98

Solution : a)

Unattempted. Explanation :-

Statement 1 is correct. Condensation is the process where water vapor becomes liquid. It is the reverse of evaporation, where liquid water becomes a vapor.

Statement 2 is correct. The dew point is the temperature the air needs to be cooled to (at constant pressure) in order to achieve a relative humidity (RH) of 100%. At this point, the air cannot hold more water in the gas form. If the air were to be cooled even more, water vapor would have to come out of the atmosphere in the liquid form, usually as fog or precipitation.

Statement 3 is incorrect. Forms of condensation can be classified on the basis of temperature and location. Condensation takes place when the dew point is lower than the freezing point as well as higher than the freezing point. After condensation, the water vapour or the moisture in the atmosphere takes one of the following forms — dew, frost, fog and clouds.

Source)

FUNDAMENTALS OF PHYSICAL GEOGRAPHY; chapter 11; page number 99

Solution : d)

Unattempted. Explanation :-

According to their height, expanse, density and transparency or opaqueness clouds are grouped under four types: (i) cirrus; (ii) cumulus; (iii) stratus; (iv) nimbus.

Nimbus clouds are black or dark gray. They form at middle levels or very near to the surface of the earth. These are extremely dense and opaque to the rays of the sun. Sometimes, the clouds are so low that they seem to touch the ground. Nimbus clouds are shapeless masses of thick vapour.

Source) FUNDAMENTALS OF PHYSICAL GEOGRAPHY; chapter 11; page number 100

 

Solution : a)

Unattempted. Explanation :-

Pair 1 is correct. A fringing reef is a coralline platform lying close to the shore extending outwards from the mainland. It is sometimes separated from the shore by a shallow lagoon.

An atoll may have any one of the following three forms:

1. True atoll—a circular reef enclosing a lagoon with no island;
2. An atoll surrounding a lagoon with an island;
3. A coral island or an atoll island which is, in fact, an atoll reef, built by the process of erosion and deposition of waves with island crowns formed on them. Hence, pair 3 is incorrect.

Pair 2 is incorrect. A barrier reef is separated from the coast by a much wider and deeper channel or lagoon. The reef is partially submerged. Thus, a little vegetation is possible where it lies above the water level and sand can accumulate on it.

Source) GC Leong; Chapter 11; Page number 81

Solution : c)

Unattempted. Explanation :-

The reef-building corals survive best under the following conditions:

1. The water temperature must not fall below 20 degrees Celsius. Hence, statement 1 is incorrect.

2. The deep of water should not exceed 30 fathoms or 180 feet because under beyond this depth sunlight is too faint for photosynthesis. Hence, statement 2 is correct.

3. The water should be saltish and free from sediment. Hence, statement 3 is correct.

Source) GC Leong; chapter 11; Page number 80

 

Solution : b)

Unattempted. Explanation :-

Statement 1 is incorrect. Continental islands were formerly part of the mainland and are now detached from the continent. They may be separated by a shallow lagoon or a deep channel. Their separation could be due to subsidence of some part of the island or to be a rise in sea level, so that the lowland links are submerged by the sea.

Statement 2 is correct. Individual islands lie just outside the continent. They are very much associated with the characteristic features of the mainland of which they were once part. Sri-Lanka is an example of Individual Island. It is separated from the Indian Mainland by the Palk Strait.

Source) GC Leong; chapter 11; Page no 79

Solution : c)

Unattempted. Explanation :-

Both the statements is are correct.

Oyashio/Oya Siwo/Okhotsk or the Kurile current is a cold subarctic ocean current that flows south and circulates counterclockwise in the western North Pacific Ocean.

The Kuroshio is a warm northeasterly ocean current off the coast of Japan. It is also called the gulf stream of the Pacific or Japan Current.

The mixing of warm and cold currents help to replenish the oxygen and favor the growth of planktons, the primary food for fish population. The best fishing grounds of the world exist mainly in these mixing zones. Example: Grand Banks around Newfoundland, Canada and North-Eastern Coast of Japan.

Source) FUNDAMENTALS OF PHYSICAL GEOGRAPHY; chapter 14; Page number 125

 

Solution : a)

Unattempted. Explanation :-

Statement 1 is correct. The shallowness of continental shelves enables sunlight to penetrate through the water, which encourages the growth of minute plants and other microscopic organisms. Therefore, they are rich in plankton on which millions of surface and bottom-feeding fishes thrive, making the continental shelves richest fishing grounds in the world. Example: the Grand Banks of Newfoundland, the North Sea and the Sunda Shelf etc. 

Statement 2 is incorrect. The limited depth and gentle slope of continental shelves keep out cold under-currents and increase the height of tides. 

Source) GC Leon; chapter 12; page number 85

 

Solution : d)

Unattempted. Explanation :-

• Option D is the Correct Answer: The factors which affect the distribution of temperature of ocean water are:
  • Latitude: The temperature of surface water decreases from the equator towards the poles because the amount of insolation decreases poleward.
  • Unequal distribution of land and water: oceans in the northern hemisphere receive more heat due to their contact with a larger extent of land than the oceans in the southern hemisphere.
  • Prevailing wind: The wind blowing from the land towards the ocean drive warm surface water away from the coast resulting in the upwelling of cold water from below. It results in the longitudinal variation in the temperature. Contrary to this, the onshore winds pile up warm water near the coast and this raises the temperature.
  • Ocean Currents: Warm ocean currents raise the temperature in cold areas while the cold currents decrease the temperature in warm ocean areas. Gulf stream (warm Current) raises the temperature near the eastern coast of North America and the West Coast of Europe while the Labrador current(Cold Current) lowers the temperature near the north-east coast of North America.

Solution : d)

Unattempted. Explanation :-

• Option D is the Correct Answer: From severe thunderstorms sometimes spiralling wind descends like a trunk of an elephant with great force, with very low pressure at the centre, causing massive destruction on its way. Such a phenomenon is called a tornado. Tornadoes generally occur in middle latitudes. The tornado over the sea is called water sprouts.

Solution : d)

Unattempted. Explanation :-

• Option D is the Correct Answer: 

 

Solution : b)

Unattempted. Explanation :-

• Option B is the Correct Answer:
  • Isohaline. : a line or surface is drawn on a map or chart to indicate connecting points of equal salinity in the ocean.
  • Isohyte: a line is drawn on a map connecting points having equal rainfall at a certain time or for a stated period

Solution : b)

Unattempted. Explanation :-

• Statement 1 is Incorrect and Statement 2 is Correct:
  • The temperature structure of oceans over middle and low latitudes can be described as a three-layer system from the surface to the bottom.
  • The first layer represents the top layer of warm oceanic water and it is about 500m thick with temperatures ranging between 20° and 25° C. This layer, within the tropical region, is present throughout the year but in mid-latitudes, it develops only during summer. The second layer called the thermocline layer lies below the first layer and is characterised by a rapid decrease in temperature with increasing depth. The thermocline is 500 -1,000 m thick. The third layer is very cold and extends up to the deep ocean floor.

Solution : d)

Unattempted. Explanation :-

• Option D is the Correct Answer: 
  • The salinity of water in the surface layer of oceans depend mainly on evaporation and precipitation.
  • Surface salinity is greatly influenced in coastal regions by the freshwater flow from rivers, and in polar regions by the processes of freezing and thawing of ice.
  • Wind also influences the salinity of an area by transferring water to other areas.
  • The ocean currents contribute to the salinity variations.
  • Salinity, temperature and density of water are interrelated. Hence, any change in the temperature or density influences the salinity of an area.

Solution : a)

Unattempted. Explanation :-

• Option A is the Correct Answer: 

The following are the factors responsible for ocean currents:

• The Planetary winds,
• Temperatures,
• Salinity,
• The earth s rotation,
• Obstruction from land

The Planetary winds

The Planetary winds are probably the dominant influence on the flow of ocean currents. The strongest evidence of prevailing winds on the flow of ocean currents can be witnessed in the North Indian Ocean where there is a change in the direction of ocean currents with a change in direction of the monsoon winds. The oceanic circulation pattern roughly corresponds to the earth s atmospheric circulation pattern.

Temperature

The differential heating of the Sun at the equator and the poles causes a difference in the temperature of ocean water. At the equator, since the temperature is higher the ocean water gets heated up and expands. This makes the warm water lighter and hence rises while at the poles, cold water is denser and sinks. Warm water from the equator slowly moves along the surface towards the poles, while the cold water from the poles slowly creeps along the bottom of the sea towards the equator.

Hence, the difference in heating and surface temperatures play a key role in the movements of ocean water.

Salinity

The density of water also depends on its salinity and the salinity of water varies from place to place. Waters of low salinity flow on the surface of waters of high salinity while waters of high salinity flow at the bottom.

The earth's rotation around the planet axis and Coriolis force

The earth's rotation deflects moving objects to the right and ocean currents are no exception. Under the action of Coriolis force, the movement of ocean currents in the northern hemisphere is in the clockwise and in the southern hemisphere it is in the anti-clockwise direction. Hence it can be said that ocean currents obey Ferrel's law.

Obstruction due to land

A landmass obstructs the direction of flow of ocean current and divides the ocean current which in turns flow in a different direction. Example: The south equatorial current in the Atlantic Ocean is obstructed by the South American continent and the South equatorial current divides to create the Brazilian current which flows in the south Atlantic Ocean.