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CDS 2025 Previous Year GK Questions with Answers

GK questions asked in CDS 2025, with answers and explanations.

Previous Year Questions

Q1.GeographyAsked in: CDS · CDS-I 2025, GKMedium

Identify the Mineral on the basis of the following characteristics relating to it : I. It is usually a greenish crystal. II. It is often found in basaltic rocks. III. Magnesium, iron and silica are its major elements. Select the answer using the code given below :

  1. A.Amphibolite
  2. B.Feldspar
  3. C.Pyroxene
  4. D.Olivine
Show answer
Correct answer: D. Olivine

Explanation

The correct answer is D, Olivine. Olivine is a silicate of magnesium and iron that forms greenish crystals and is common in basalt.

Olivine takes its name from its olive-green colour. It crystallises early from hot magma that is low in silica, which is why it turns up in basalt, gabbro and peridotite and makes up much of the Earth's upper mantle. Its main elements are magnesium, iron and silica. A clear, gem-quality olivine is sold as the jewel peridot. Feldspar and quartz, by contrast, are the commonest minerals of the crust and are richer in silica.

A is wrong: amphibolite is a metamorphic rock made mostly of amphibole minerals, not a single mineral.

B is wrong: feldspar is made of silicon and oxygen with sodium, potassium, calcium and aluminium, and is light cream to salmon pink.

C is wrong: pyroxene contains calcium and aluminium along with magnesium, iron and silica, and is usually green or black.

Exam tip: olivine = green, Mg-Fe silicate, basalt, gem peridot; feldspar = half of the crust.

Q2.Indian PolityAsked in: CDS · CDS-II 2025, GKEasy

Which one of the following features is correct about the 'First Past the Post System' of election ?

  1. A.A candidate who wins may not get the majority of votes
  2. B.More than one representative may be elected from one constituency
  3. C.Voters vote for the party, not the candidate
  4. D.Every party gets seats in the legislature in proportion to percentage of votes that it gets
Show answer
Correct answer: A. A candidate who wins may not get the majority of votes

Explanation

The correct answer is A, A candidate who wins may not get the majority of votes. Under First Past the Post, the candidate with the most votes wins, even if that is far less than half of all votes cast. This is also UPSC's official key.

India uses this system, also called the simple plurality system, for elections to the Lok Sabha and the state Legislative Assemblies. The country is divided into constituencies, each electing one member, and voters choose a candidate rather than a party. In a contest of many candidates, someone with 35% of the votes can win if no rival does better. As a result, a party's share of seats can be much larger or smaller than its share of votes.

B is wrong: First Past the Post uses single-member constituencies, so each one elects only one representative.

C is wrong: voting for a party list is a feature of proportional representation, not of First Past the Post.

D is wrong: seats in proportion to votes is exactly what proportional representation aims at.

Exam tip: India uses FPTP for Lok Sabha and Assemblies, and proportional representation by single transferable vote for Rajya Sabha and the President.

Q3.GeographyAsked in: CDS · CDS-I 2025, GKMedium

Consider the following statements with reference to Secondary waves (S-Waves) generated during an earthquake : 1. They create troughs and crests in the material through which they pass. 2. The direction of vibrations of S-waves is perpendicular to the wave direction in the vertical plane. Which of the statements given above is/are correct ?

  1. A.1 only
  2. B.2 only
  3. C.Both 1 and 2
  4. D.Neither 1 nor 2
Show answer
Correct answer: C. Both 1 and 2

Explanation

The correct answer is C, Both 1 and 2. S-waves are transverse waves: they shake the ground at right angles to their direction of travel, and that sideways motion forms crests and troughs.

An earthquake sends out two kinds of body waves. P-waves (primary) are the fastest and work like sound waves, pushing and pulling the material in the same direction as the wave moves; they pass through solids, liquids and gases. S-waves (secondary) arrive later and vibrate the material perpendicular to the wave direction in the vertical plane, which is why they create troughs and crests. S-waves travel only through solids, and their absence beyond the shadow zone told scientists that the outer core is liquid.

A is wrong: statement 2 is also correct, since the perpendicular vibration is what defines an S-wave.

B is wrong: statement 1 is correct too, as the crests and troughs follow from that vibration.

D is wrong: both statements describe S-waves accurately.

Exam tip: P-waves are longitudinal and go through all states of matter; S-waves are transverse and go through solids only.

Q4.Indian HistoryAsked in: CDS · CDS-II 2025, GKMedium

Consider the following international events : 1. Signing of the Simla Agreement 2. Agra Summit between India and Pakistan 3. Signing of the SAARC Charter at the First SAARC Summit 4. India's first nuclear test Which one of the following is the correct chronological order of the above events ?

  1. A.1, 3, 4, 2
  2. B.4, 1, 3, 2
  3. C.1, 4, 3, 2
  4. D.4, 1, 2, 3
Show answer
Correct answer: C. 1, 4, 3, 2

Explanation

The correct answer is C, 1, 4, 3, 2. The events fall in 1972, 1974, 1985 and 2001 in that order, which is also UPSC's official key.

The Simla Agreement was signed on 2 July 1972 by Indira Gandhi and Zulfikar Ali Bhutto after the 1971 war; it turned the ceasefire line in Kashmir into the Line of Control. India's first nuclear test, code-named Smiling Buddha, was held at Pokhran on 18 May 1974. The SAARC Charter was signed at the first summit in Dhaka on 8 December 1985. The Agra Summit between Atal Bihari Vajpayee and Pervez Musharraf took place in July 2001 and ended without a joint declaration.

A is wrong: it puts the 1985 SAARC Charter before the 1974 test.

B is wrong: it starts with the 1974 test, but the Simla Agreement came two years earlier.

D is wrong: it begins with the test and also places the 2001 Agra Summit before the 1985 SAARC Charter.

Exam tip: Simla 1972, Pokhran-I 1974, SAARC Dhaka 1985, Lahore bus 1999, Agra 2001.

All Defence previous year questions