Rocks and The Volcano

Q1. Which type of rock is formed from cooling and solidification of lava? 70th B.P.S.C. Pre-2024

(a) Igneous

(b) Sedimentary

(d) Metamorphic

Ans. (a)

Explanation:

Igneous rocks are formed by the cooling and solidification of magma or lava. They are classified into two types: intrusive and extrusive igneous rocks.
Extrusive igneous rocks are formed when magma comes out from the Earth's interior through volcanic eruptions and cools and solidifies on the Earth's surface. Basalt is an example of an extrusive igneous rock.
Intrusive igneous rocks are formed when magma solidifies within the Earth's crust. Granite is an example of an intrusive igneous rock.

Hence, option (a) is correct.

Q2. Consider the following statements about the sedimentary rocks: I.A.S. (Pre) 2001

Sedimentary rocks are formed at the earth's surface by the hydrological system.
The formation of sedimentary rocks involves the weathering of preexisting rocks.
Sedimentary rocks contain fossils.
Sedimentary rocks typically occur in layers.

Which of these statements are correct?

(a) 1 and 2

(b) 1 and 4

(d) 1, 2, 3 and 4

Ans. (d)

Explanation:

Sedimentary rocks are formed at the Earth's surface by the accumulation and deposition of sediments through the hydrological system. Hence, statement 1 is correct.
The formation of sedimentary rocks involves the weathering and erosion of preexisting rocks, which produce sediments that later form sedimentary rocks. Hence, statement 2 is correct.
Sedimentary rocks often contain fossils because the remains of plants and animals get preserved during the process of sediment deposition. Hence, statement 3 is correct.
Sedimentary rocks are generally found in layers called strata due to the successive deposition of sediments. Hence, statement 4 is correct.

Hence, option (d) is correct.

Q3. Consider the following statements: I.A.S. (Pre) 2025

Statement I: In the context of effect of water on rocks, chalk is known as a very permeable rock whereas clay is known as quite an impermeable or least permeable rock.

Statement II: Chalk is porous and hence can absorb water.

Statement III: Clay is not at all porous.

Which one of the following is correct in respect of the above statements?

(a) Both Statement II and Statement III are correct and both of them explain Statement I.

(b) Both Statement II and Statement III are correct but only one of them explains Statement I.

(d) Neither Statement II nor Statement III is correct.

Ans. (c)

Explanation:

Porosity refers to the amount of voids or pores present within a rock, which determines its capacity to store water. Permeability refers to the ability of water to flow through a rock due to the connection of these pores.
Chalk is a highly porous rock and can absorb and store water. Due to interconnected cracks and fractures, it also acts as a highly permeable aquifer at a regional scale.
Hence, Statement II is correct and it explains Statement I.
Clay contains a high volume of pores and is considered a porous sediment. However, its pores are very small and poorly connected, making it the least permeable and capable of restricting water flow.
Hence, Statement III is incorrect.
Therefore, only Statement II correctly explains why chalk is permeable, while Statement III is incorrect because clay is porous but has very low permeability.

Hence, option (c) is correct.

Q4. Consider the following statements: I.A.S. (Pre) 2024

Statement-I: Rainfall is one of the reasons for weathering of rocks.

Statement-II: Rain water contains carbon dioxide in solution.

Statement-III: Rain water contains atmospheric oxygen.

Which one of the following is correct in respect of the above statements?

(a) Both Statement-II and Statement-III are correct and both of them explain Statement-I.

(b) Both Statement-II and Statement-III are correct, but only one of them explains Statement-I.

(d) Neither Statement-II nor Statement-III is correct.

Ans. (a)

Explanation:

Weathering is the process of breakdown of rocks due to physical and chemical changes. Rainfall influences chemical weathering, and regions with high rainfall and temperature experience faster weathering of rocks. Hence, Statement-I is correct.
Rainwater absorbs carbon dioxide present in the atmosphere and forms weak carbonic acid. This acid reacts with rocks, especially limestone, causing their chemical decomposition through the process of carbonation. Hence, Statement-II is correct and it explains Statement-I.
Rainwater also contains dissolved atmospheric oxygen, which reacts with minerals, especially iron-bearing minerals, through oxidation. This process forms oxides and weakens rocks, contributing to weathering. Hence, Statement-III is correct and it explains Statement-I.
Since both dissolved carbon dioxide and oxygen in rainwater contribute to the weathering of rocks, both Statement-II and Statement-III explain Statement-I.

Hence, option (a) is correct.

Q5. Consider the following: I.A.S. (Pre) 2024

Pyroclastic debris
Ash and dust
Nitrogen compounds
Sulphur compounds

How many of the above are products of volcanic eruptions?

(a) Only one

(b) Only two

(d) All four

Ans. (d)

Explanation:

Volcanic eruptions release various materials such as molten rock material (lava), gases, ash, and other solid fragments from the Earth's interior.
Pyroclastic debris consists of fragmented volcanic materials ejected during eruptions. Hence, statement 1 is correct.
Ash and dust are fine volcanic particles released into the atmosphere during volcanic eruptions. Hence, statement 2 is correct.
Volcanic gases include compounds such as nitrogen compounds and sulphur compounds, along with minor amounts of chlorine, hydrogen, and argon. Hence, statement 3 and statement 4 are correct.

Therefore, all the given materials are products of volcanic eruptions.

Hence, option (d) is correct.

Q6. Which one of the following is the highest volcanic mountain in the world? U.P.P.C.S. (Pre) 2015

(a) Mount Pinatubo

(b) Mount Kilimanjaro

(d) Mount Cotopaxi

Ans. (d)

Explanation:

Mount Cotopaxi, with a height of 5911 m, is the highest volcanic mountain among the given options.
Mount Kilimanjaro has a height of 5881 m, Mount Pinatubo has a height of 1486 m, and Mount Tall has a height of 311 m and is located in the Philippines.

Hence, option (d) is correct.

Q7. Volcanic eruptions do not occur in the: I.A.S. (Pre) 2001

(a) Baltic Sea

(b) Black Sea

(d) Caspian Sea

Ans. (a)

Explanation:

Volcanic eruptions are mainly associated with plate boundaries, especially regions of plate convergence and divergence.
Among the given options, the Baltic Sea is not located near any active plate boundary zone. Therefore, volcanic activity does not occur there.
The Black Sea, Caribbean Sea, and Caspian Sea regions are associated with tectonic activity, while the Baltic Sea lacks such volcanic activity.

Hence, option (a) is correct.

Q8. Mt. Etna is – 43rd B.P.S.C. (Pre) 1994

(a) A mountain

(b) A mountain peak

(d) A plateau

Ans. (c)

Explanation:

Mount Etna is an active volcano located on the east coast of Sicily, Italy.
It has a maximum height of about 3357 meters and is one of the most active volcanic regions in the world.
Hence, option (c) is correct.

Q9. Where is the Mount Saint Helens situated? I.A.S. (Pre) 2005

(a) Chile

(b) Japan

(d) United State of America

Ans. (d)

Explanation:

Mount Saint Helens is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States of America.
Hence, option (d) is correct.

Q10. Mauna Loa is an active volcano in – U.P.P.C.S. (Mains) 2014; U.P.P.C.S. (Pre) 2005

(a) Alaska

(b) Hawaii

(d) Japan

Ans. (b)

Explanation:

Mauna Loa is an active volcano located on the island of Hawaii, USA. In the Hawaiian language, Mauna Loa means the "Long Mountain".
Hence, option (b) is correct.
It is one of the world's active volcanoes, with its first well-documented eruption recorded in 1843. It covers nearly half of the Hawaii Island.

Hence, option (b) is correct.

Q11. Which of the following is the World's largest volcano erupted for the first time in 38 years? 68th B.P.S.C. (Pre) 2022

(a) Haleakala

(b) Mount St. Helens

(d) More than one of the above

(e) None of the above

Ans. (c)

Explanation:

Mauna Loa, located in Hawaii (USA), is the world's largest volcano and one of the most active volcanoes. It erupted in November 2022 after a 38-year interval since its previous eruption in 1984.
Hence, option (c) is correct.
The Hawaiian name "Mauna Loa" means "Long Mountain". The name is appropriate because the above-sea-level part of the volcano extends about 120 km from the southern tip of the island to the summit caldera and further east-northeast towards the coastline near Hilo.

Hence, option (c) is correct.

Q12. Which of the following are active volcanoes? U.P.P.C.S. (Mains) 2007

Aconcagua
Cotopaxi
Etna
Fujiyama

Select the correct answer from the code given below:

(a) 1 and 2

(b) 3 and 4

(d) 2, 3 and 4

Ans. (d)

Explanation:

Cotopaxi, located in Ecuador, is an active stratovolcano in the Andes.
Hence, statement 2 is correct.
Mount Etna, located on the island of Sicily, Italy, is one of the world’s most active volcanoes.
Hence, statement 3 is correct.
Mount Fuji (Fujiyama), located in Japan, is an active stratovolcano. Although it has not erupted since 1707, it is classified as an active volcano.
Hence, statement 4 is correct.
Aconcagua, located in Argentina near the Chilean border, is the highest mountain in the Americas. It is not a volcano and is therefore not an active volcano.
Hence, statement 1 is incorrect.

Therefore, Cotopaxi, Etna and Mount Fuji are active volcanoes, while Aconcagua is not.

Hence, the correct answer is (d) 2, 3 and 4.

Q13. The Arctic region and the Antarctica continent are situated near: 68th B.P.S.C. (Pre) 2022

(a) the Amazon Basin

(b) the Sahara Desert

(d) More than one of the above

(e) None of the above

Ans. (c)

Explanation:

The Arctic region is located around the North Pole and includes the Arctic Ocean and the northern parts of countries such as Canada, Russia, the United States (Alaska), Greenland, and Norway.
Hence, the Arctic region is situated near the North Pole.
Antarctica is the southernmost continent, surrounding the South Pole. About 98% of its land surface is covered by ice.
Hence, Antarctica is situated near the South Pole.
Therefore, the Arctic and Antarctica are located near the North and South Poles, respectively.

Hence, the correct answer is (c) North and South Poles.

Q14. Match List-I with List-II and select the correct answer using the code given below the list: U.P.P.C.S (Pre) 2010

List-I List-II

A. Etna 1. Ross Island

B. Vesuvius 2. Ecuador

C. Erebus 3. Italy

D. Cotopaxi 4. Sicily

Code:

A B C D

(a) 1 2 3 4

(b) 4 3 1 2

(d) 4 3 2 1

Ans. (b)

Explanation:

Mount Etna is an active volcano located on the east coast of the Mediterranean Sea's Sicily Island. Hence, A is correctly matched with 4.
Mount Vesuvius is situated at the Bay of Naples in Italy. Hence, B is correctly matched with 3.
Mount Erebus is an active volcano located on Ross Island in Antarctica. Hence, C is correctly matched with 1.
Cotopaxi is an active volcano located in the Andes mountain region of Ecuador. Hence, D is correctly matched with 2.

Therefore, the correct matching is A-4, B-3, C-1, D-2.

Q15. Match List -I and List-II and select correct answer from the code given below: U.P.P.C.S. (Mains) 2015

List-I List-II

A. Mount Kinabalu 1. Argentina

B. Elburz 2. Malaysia

C. Aconcagua 3. Tanzania

D. Kilimanjaro 4. Iran

Code:

A B C D

(a) 1 4 2 3

(b) 3 2 1 4

(d) 2 4 1 3

Ans. (d)

Explanation:

Mount Kinabalu is located in Malaysia; hence, pair A–2 is correctly matched.
Elburz mountain range is located in Iran; hence, pair B–4 is correctly matched.
Aconcagua, the highest peak of South America, is situated in Argentina; hence, pair C–1 is correctly matched.
Mount Kilimanjaro, the highest peak of Africa, is located in Tanzania; hence, pair D–3 is correctly matched.
Hence, option d is correct.

Q16. Match List-I with List-II and select the correct answer from the codes given below the lists: U.P.P.C.S. (Pre) 2015

List-I (Volcano) | List-II (Country)

A. Sabancaya | 1. Italy

B. Mount Etna | 2. Peru

C. Colima | 3. Indonesia

D. Merapi | 4. Mexico

Code:

A B C D

(a) 3 1 4 2

(b) 3 2 1 4

(d) 4 3 2 1

Ans. (c)

Explanation:

Sabancaya volcano is located in Peru; hence, pair A–2 is correctly matched.
Mount Etna, one of the active volcanoes of Europe, is situated in Italy; hence, pair B–1 is correctly matched.
Colima volcano is located in Mexico; hence, pair C–4 is correctly matched.
Mount Merapi is an active volcano situated in Indonesia; hence, pair D–3 is correctly matched.

Hence, option c is correct.

Q17. Match List - I with List - II and select the correct answer using the codes given below the lists: U.P.P.C.S. (Pre) 2021

List - I (Volcanic Mountains) | List - II (Country)

A. Mount Rainier | 1. Italy

B. Mount Etna | 2. Mexico

C. Mount Paricutin | 3. Philippines

D. Mount Apo | 4. U.S.A.

Codes:

A B C D

(a) 4 2 1 3

(b) 4 1 2 3

(d) 4 3 2 1

Ans. (b)

Explanation:

Mount Rainier is a volcanic mountain located in the U.S.A.; hence, pair A–4 is correctly matched.
Mount Etna, one of the most active volcanoes in the world, is situated in Italy; hence, pair B–1 is correctly matched.
Mount Paricutin is a volcanic mountain located in Mexico; hence, pair C–2 is correctly matched.
Mount Apo, the highest peak of the Philippines, is a volcanic mountain situated in the Philippines; hence, pair D–3 is correctly matched.
Hence, option b is correct.