UPSC MCQ: Physical Geography- 1 - UPSC MCQ

Rather, the term is derived from the concept of the tide "springing forth." Spring tides occur twice each lunar month all year long without regard to the season. Neap tides, which also occur twice a month, happen when the sun and moon are at right angles to each other.  Statement 1 is correct.

There is a seven day interval between the spring tides and neap tides. At this time the sun and moon are at right angles to each other and the forces of the sun and moon tend to counteract one another. Statement 2 is correct.

Answer: c)

Explanation: Major ocean currents are greatly influenced by the stresses exerted by the prevailing winds and coriolis force. The oceanic circulation pattern roughly corresponds to the earth’s atmospheric circulation pattern. The air circulation over the oceans in the middle latitudes is mainly anticyclonic (more pronounced in the southern hemisphere than in the northern hemisphere). The oceanic circulation pattern also corresponds with the same. At higher latitudes, where the wind flow is mostly cyclonic, the oceanic circulation follows this pattern.

• Definition: Upward and downward movement of ocean water is known as tides.



• Causes: Tides are primarily caused by the gravitational pull of the moon and the sun on the Earth's water.



• Types of Tides: There are mainly two types of tides: high tide and low tide, which occur approximately twice a day.



• High Tide: High tide is when the water level rises to its highest point, and it is usually followed by low tide.



• Low Tide: Low tide is when the water level drops to its lowest point, exposing more of the shoreline.

Answer: a)

Explanation: Groundwater 0.68%, Lakes 0.01%, Soil Moisture 0.005%, Atmosphere 0.001%, Streams and Rivers 0.0001%, Biosphere 0.00004%.

Answer: c)

Explanation: The continental shelf is the extended margin of each continent occupied by relatively shallow seas and gulfs. It is the shallowest part of the ocean showing an average gradient of 1° or even less. The shelf typically ends at a very steep slope, called the shelf break.

Seamount It is a mountain with pointed summits, rising from the seafloor that does not reach the surface of the ocean. Seamounts are volcanic in origin. These can be 3,000-4,500 m tall. The Emperor seamount, an extension of the Hawaiian Islands in the Pacific Ocean, is a good example.

Answer:  d)

Explanation: The factors which affect the distribution of temperature of ocean water are Latitude, Unequal distribution of land and water, Prevailing wind and Ocean currents.

Sure, let's break down each statement:

1. About 90 per cent of the total volume of water is found below the thermocline in the deep ocean.

This statement is generally correct. The thermocline is a layer in the ocean where temperature changes rapidly with depth. Below the thermocline is the deep ocean, where temperatures are more uniform. So, most of the water volume in the ocean is indeed found below the thermocline.

1. In the thermocline zone, temperatures approach 0°C.

This statement is not correct. The thermocline is characterized by a rapid change in temperature with depth, but it does not necessarily approach 0°C. The temperature in the thermocline can vary depending on factors such as location, depth, and season.

Therefore, the correct answer is:

1. Only 2.

Answer: d)

Explanation: Factors affecting ocean salinity are mentioned below:

(i) The salinity of water in the surface layer of oceans depends mainly on evaporation and precipitation.

(ii) Surface salinity is greatly influenced in coastal regions by the fresh water flow from rivers, and in Polar Regions by the processes of freezing and thawing of ice.

(iii) Wind, also influences salinity of an area by transferring water to other areas.

(iv) 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 water in an area.

Answer: a)

Explanation: The actual amount of the water vapour present in the atmosphere is known as the absolute humidity. It is the weight of water vapour per unit volume of air and is expressed in terms of grams per cubic metre.

Answer: c)

Explanation: Cirrus clouds are formed at high altitudes (8,000 - 12,000m). They are thin and detatched clouds having a feathery appearance. They are always white in colour.

Evaporation happens when a liquid substance becomes a gas. When water is heated, it evaporates. The molecules move and vibrate so quickly that they escape into the atmosphere as molecules of water vapor.

Answer: c)

Explanation: The, air on being heated, becomes light and    rises up in convection currents. As it rises, it expands and loses heat and consequently, condensation takes place and cumulous clouds are formed. With thunder and lightening, heavy rainfall takes place but this does not last long. Such rain is common in the summer or in the hotter part of the day. It is very common in the equatorial regions and interior parts of the continents, particularly in the northern hemisphere.

Near the equator, from about 5° north and 5° south, the northeast trade winds and southeast trade winds converge in a low pressure zone known as the intertropical convergence zone (ITCZ)

Eskimos are the indigenous circumpolar people who have traditionally inhabited the northern circumpolar region from eastern Siberia (Russia) to Alaska (United States), Canada, and Greenland (Denmark).

Polar Region: The part of the Earth's surface forms a cap over a pole; characterized by a frigid climate. There are two main polar regions in the world, which are the Arctic and the Antarctic. The Arctic Circle and Arctic Tundra are found at the North Pole, and it covers nearly 5 million square miles of the top of the Northern Hemisphere.

In the Northern Hemisphere, wind flows in an anticlockwise direction around areas of low pressure. This is due to the Coriolis effect, which is a result of the Earth's rotation.

Answer: a)

Explanation: They are known as Cyclones in the Indian Ocean, Hurricanes in the Atlantic, Typhoons in the Western Pacific and South China Sea, and Willy-willies in the Western Australia.

Answer: c)

Explanation: If an air mass is fully lifted above the land surface, it is called the occluded front. The fronts occur in middle latitudes and are characterised by steep gradient in temperature and pressure.

The correct option is Option C.
At that time, sun's rays are overhead at the tropic of cancer (23.5°N). The Tropic of Cancer passes through the middle of India. It remains till the end of May in India. Before summer solstice i.e., 21st June, monsoon starts in India which brings a cooling effect to the climate of India.

• Short wave solar radiation: Short wave solar radiation from the sun enters the Earth's atmosphere, but it is not the main source of heating for the atmosphere.


• Reflected solar radiation: Reflected solar radiation is the sunlight that is bounced back into space by clouds, snow, ice, and other reflective surfaces. It does not contribute significantly to heating the atmosphere.


• Long wave terrestrial radiation: The Earth absorbs the short wave solar radiation and re-emits it as long wave terrestrial radiation. This long wave radiation is the main source of heating for the atmosphere. It is also known as terrestrial radiation or infrared radiation.


• Scattered solar radiation: Scattered solar radiation occurs when particles in the atmosphere disperse sunlight in different directions. While some of this scattered radiation may contribute to heating, it is not the primary source of atmospheric heating.

Answer: d)

Explanation: Tropical cyclone does not form over the equator because the coriolis force is zero at the equator. Even though equator is a zone of wind convergence, it has nothing to do with tropical cyclone as such. Temperature is highest north and south of equator and not exactly at equator. Fronts are required for formation of temperate cyclone and not tropical ones. So even though statement 3 is correct it is not a reason.

Answer c)

Explanation: Laterite soil is primarily found in the tropical regions which receive heavy seasonal rainfall. High rainfall encourages the leaching of soil where lime and silica are leached away and a soil rich in oxides of aluminum predominate and abundance laterite is called bauxite. Due to the presence of iron oxides the colour of laterite soil is basically red. This soil is poor in organic matter and lime content.

Answer: b)

Explanation: They occur in wet spells of few days duration at a time.

 Answer: c)

Explanation: Deltas shrink due to lack of sediments and not due to huge amount of sediments. A proliferation of large dams that starve deltas of sediment, groundwater mining that causes land compaction, and artificial levees that affect river courses, have been responsible for the subsiding of major Indian deltas including Ganga-Brahmaputra, Krishna-Godavari, Brahmani and Mahanadi

- Crossing the International Date Line from east to west, you gain a day. From west to east, you lose a day. This is due to the way time zones are structured globally.
- The International Date Line isn't a straight line. It deviates around the Bering Strait, Fiji, Tonga, and other islands to avoid splitting countries or islands into different days, minimizing confusion.
- Both statements are accurate, confirming why the correct answer is D: Both 1 and 2.

Correct answer is D.

C is the correct option.
If the surface air pressure is 1,000 mb, the air pressure at 1 km above the surface will be: The air pressure decreases by 1 mb for every increase bof 10 m in height
Since, height increased = 1 km
Air pressure decrease by units = 1000/10 = 100 units

Hence, pressure at 1 km above will be
1000 - 100 = 900 mb
 

The correct option is Option C.
Air masses are formed when the air above huge homogeneous areas acquires the characteristics of the area. This leads to the air having little horizontal variations in form. Accordingly,
C is correct, as it is a cold, large and homogeneous mass of land.
A is incorrect, as the size of the forested areas are not large enough to create air-mass
B is incorrect, as Himalayas do not constitute a homogeneous platform.
D is incorrect due to regional variations across the Deccan Plateau.

The pressure exerted by air on the surface of the earth is called as atmospheric pressure. The pressure varies from region to region.

Continental Polar air masses form over large, high- latitude land masses, such as northern Canada or Siberia. cP air masses are cold and extremely dry. Wintertime cooling over these land areas cause the atmosphere to become very stable.