Physical Geography (UPSC) (Part-I)

Total Questions: 50

11. Daily weather map showing isobars is an example of: [1997]

Correct Answer: (b) Isopleth map
Solution:Daily weather map showing isobars is an example of an isopleth map.
Isopleth maps show an imaginary surface by means of lines joining points of equal values.
• Isotherm: Connects points of equal temperature.
• Isobar: Connects points of equal atmospheric pressure.
• Isohyet: Connects points of equal rainfall.
• Isobath: Connects points of equal depth, often used in oceanography.
• Contour Lines: Connect points of equal elevation.

12. The group of small pieces of rock revolving round the sun between the orbits of Mars and Jupiter are called: [1997]

Correct Answer: (d) asteroids  
Solution:

COMET: A Mass of ice, rock and dust drifting in space that often has a tail, which grows as it gets closer to the Sun. The tail is made up of water, dust and various gases vaporized by solar energy,
ASTEROID: A body made up of rocks, both metallic and non-metallic, that orbits the Sun, usually in the asteroid belt between Mars and Jupiter. Some Asteroids are Comet Nuclei. They range in size from a few centimeters to a thousand kilometers.
METEOROID: A rock, often an asteroid fragment, that is bigger than a grain of sand and orbits the Sun. The term "meteoroid" refers to the object before it enters the atmosphere.
METEOR: A Meteoroid that enters the Earth's atmosphere becomes a meteor. It burns up as it travels through the atmosphere (mesosphere), producing a streak of light. A meteor can arrive in Earth's vicinity as a lone object (shooting star) or in clusters (meteor shower).

13. If the earth's direction of rotation is reversed, what should be the IST when it is noon at the International Date Line? [1997]

Correct Answer: (a) 06.30 hrs
Solution:The earth rotates on its axis from west to east direction and in this condition, the international standard time at 82½° longitude is ahead by 5:30 hours from the International Date Line (180°).
Since 1° = 4 minutes, the Indian Standard Time at 97½° longitude will be 18:30 hours (6 hours 30 minutes ahead).
If the earth starts rotating from east to west, the time difference would reverse accordingly.

14. Which one of the following stars is nearest to the Earth? [1997]

Correct Answer: (c) Sun
Solution:

• The nearest star system to the Earth is the Alpha Centauri triple-star system which is about 4.37 light-years ≈ 40 trillion Km away from the earth.
• The Alpha Centauri triple-star system consists of three stars named Alpha Centauri A, Alpha Centauri B, and Proxima Centauri.
• Among these stars, Proxima Centauri is slightly closer as compared to Alpha Centauri A and Alpha Centauri B at 4.24 light-years away from the earth, which makes it nearest star to the earth.
• Proxima Centauri was discovered by a Scottish astronomer Robert T. A. Innes in 1915. It is sometimes also called Alpha Centauri C.
• Sirius is the brightest star in the sky which is also known as the Dog Star or Alpha Canis Majoris. Arcturus is the fourth brightest star in the sky and the brightest in the northern celestial hemisphere.
• Arcturus is also the brightest star in the constellation of Bootes.
• Spica is also one of the brightest stars in the sky. It is the brightest star in the constellation of Virgo.

15. Which one of the following conditions is most relevant for the presence of life on Mars? [1997]

Correct Answer: (c) Occurrence of ice caps and frozen water
Solution:Mars is the only planet with similar daytime temperatures and an atmosphere similar to Earth.
The most relevant condition for the presence of life on Mars is the occurrence of ice caps and frozen water.
Exploration of Mars serves multiple scientific and existential purposes. It offers insights into the formation and evolution of planets, potentially revealing whether Mars once harbored life. Understanding Mars' past environments, which might have been suitable for life, provides crucial data on planetary evolution and climate change.
Living on Mars presents formidable challenges due to its harsh environment. Mars has a thin carbon dioxide atmosphere, extreme cold, radiation exposure, and the soil contains toxic compounds. However, significant strides in technology may eventually make human settlement possible.

16. Consider the map given below: [1997]

Of the four shaded areas in the map, which is characterised by hot dry summers, mild and moist winters and seasonal reversal of winds.

Correct Answer: (a) 1
Solution:In the given world map ‘1’ refers to the hot, dry summers, and mild and moist winters in California (U.S.A.), characteristic of the Mediterranean type of climate.
• The Mediterranean climate is characterized by hot, dry summers and mild, wet winters. This climate is primarily found around the Mediterranean Basin, but also occurs in regions like southern California, central Chile, parts of South Africa, and southwestern Australia.
• It is influenced by the subtropical high-pressure system, resulting in dry summers and wet winters.
• During the summer months, high-pressure systems dominate, bringing clear skies, high temperatures, and minimal rainfall. In contrast, the winter season is marked by lower pressure, which brings cooler temperatures and more precipitation.
• These seasonal variations contribute to the development of unique vegetation, such as olive trees, vineyards, and shrubs like chaparral and maquis.
• Mediterranean climates support diverse ecosystems, including rich biodiversity, fertile agricultural land, and scenic landscapes.
• However, due to its arid summers and seasonal rainfall, regions with a Mediterranean climate are susceptible to drought and wildfire risks, making sustainable land management essential for maintaining ecological balance.

17. Consider the following statements regarding asteroids: [1998]

1. Asteroids are rocky debris of varying size orbiting the sun

2. Most of the asteroids are small but some have diameter as large and 1000 km

3. The orbit of asteroids lies between the orbits of Jupiter and Saturn Of these statements:

Correct Answer: (c) 1 and 2 are correct
Solution:The asteroids are a group of small pieces of rocky debris of different sizes. Some asteroids are small, while some asteroids even have a diameter of 1000 km. The asteroids revolve between Mars and Jupiter.

• Asteroids are also classified by structure, including monolithic (solid rocks), differentiated (layered with core, mantle, and crust), and rubble-pile asteroids held together by gravity. The classification of asteroids by structure is as follows:

• Monolithic Asteroids: Solid, single rock formations, representing the building blocks of planets.
• Differentiated Asteroids: Contain a metallic core, a mantle, and a crust, resembling small planets. Example: Vesta has a layered structure like an egg.
• Rubble Pile Asteroids: Loose aggregates of rocks and dust held together by gravity. Example: Bennu, which behaves like a space cushion due to its porous nature.

18. Match the rivers labelled A, B, C and D on the given map with their names given in the list and select the correct answer using the codes given below the lists: [1998]

 

1. St. Lawrence

2. Orinoco

3. Mackenzie

4. Amazon

5. Yukon   

ABCD
(a)4321
(b)5312
(c)5413
(d)3142

Correct Answer: (b)
Solution:

In the given diagram of North America and South America:

‘a’ marked river is Yukon

‘b’ marked river is Mackenzie

‘c’ marked river is St. Lawrence

‘d’ marked river is Orinoco.

19. The correct sequence of different layers of the atmosphere from the surface of the Earth upwards is: [1998]

Correct Answer: (c) Troposphere, Stratosphere, Mesosphere, Ionosphere
Solution:

The correct sequence of different layers of the atmosphere from the surface of the Earth is Troposphere, Stratosphere, Mesosphere, and Ionosphere.

Troposphere extends up to 8 km from the Earth's surface, but at the equator, it is 16-18 km.

Stratosphere extends above the troposphere from 18-50 km.

Mesosphere extends up to 80 km, and above the mesosphere,

Ionosphere is present, which extends up to 400 km

20. Estuaries possess distinct blooms of excessive growth of a pigmented dinoflagellates. These blooms are called [1998]

Correct Answer: (a) red tides
Solution:

Red tides are a special type of blooms, which are found at the estuaries. These blooms are pigmented dinoflagellates. These single celled organisms are able to swim short distances. When the algae is present in high concentration, the water appears purple or pink in colour .
Sea tides are the regular rise and fall of sea levels caused primarily by the gravitational pull of the moon and the sun on the Earth's oceans.
"Black tide" is a term commonly used to describe large-scale oil spills in the ocean or sea, where oil covers the surface of the water, turning it black.
"Sea flowers" is a poetic or informal term that can refer to marine plants or plant-like organisms, especially those that look like flowers under the sea.