Defence Technology — Practice Questions
UPSC Prelims-pattern practice questions on defence technology with full explanations — Mission Shakti, scramjets, nuclear doctrine, BrahMos and INS Vikrant.
Questions
These are original UPSC-pattern practice questions. Attempt each one before revealing the answer.
With reference to Mission Shakti, consider the following statements:
- It was conducted in March 2019.
- The target was a satellite in geostationary orbit.
- With it, India became the fourth country to demonstrate an anti-satellite capability.
Which of the statements given above is/are correct?
Solution
Statements 1 and 3 are correct — the test took place on 27 March 2019, after the USA, Russia and China had demonstrated ASAT capability. Statement 2 is incorrect — the target was an Indian satellite in low Earth orbit (about 300 km), chosen so that debris would decay quickly.
Answer: A
Which one of the following statements about a scramjet engine is correct?
Solution
A scramjet (supersonic combustion ramjet) burns fuel in air that stays supersonic inside the engine. It has no compressor and works only at very high speed — a rocket must first accelerate it, so A is wrong. It is air-breathing, taking oxygen from the atmosphere (B is wrong), and it is not a cryogenic rocket engine (D is wrong).
Answer: C
Consider the following with reference to India’s nuclear doctrine made public in 2003:
- No first use of nuclear weapons.
- Building and maintaining a credible minimum deterrent.
- Nuclear retaliation can be authorised only by the civilian political leadership through the Nuclear Command Authority.
- Nuclear weapons may be used first against non-nuclear-weapon states.
How many of the above are features of the doctrine?
Solution
Items 1, 2 and 3 are features of the doctrine. Item 4 is the reverse — the doctrine commits India to non-use of nuclear weapons against non-nuclear-weapon states. Three are correct.
Answer: C
Consider the following statements about BrahMos:
- It is produced by a joint venture of India and Russia.
- Its name is derived from the Brahmaputra and the Moskva rivers.
- It is a subsonic cruise missile.
Which of the statements given above is/are correct?
Solution
Statements 1 and 2 are correct — BrahMos Aerospace (1998) is an India–Russia joint venture named after the two rivers. Statement 3 is incorrect — BrahMos is supersonic (about Mach 2.8). India’s subsonic cruise missile is Nirbhay.
Answer: B
Which of the following is India’s first indigenously designed and built aircraft carrier, commissioned in September 2022?
Solution
INS Vikrant, built at Cochin Shipyard, was commissioned on 2 September 2022. INS Vikramaditya was bought from Russia; INS Viraat was a British-built carrier, now decommissioned; INS Arihant is a nuclear-powered ballistic missile submarine.
Answer: D
What is a nuclear triad? Explain its significance for India’s policy of credible minimum deterrence.
Solution
Introduction: A nuclear triad is the ability to deliver nuclear weapons from land-based missiles, aircraft and submarines. India completed its triad when INS Arihant finished its first deterrence patrol in November 2018.
Body:
- Components: land — Agni series; air — nuclear-capable combat aircraft; sea — Arihant-class submarines with K-series missiles (INS Arighaat commissioned 2024).
- Why it matters under no first use: a no-first-use policy depends on surviving a first strike and retaliating; a submarine at sea is the hardest leg to locate and destroy, so it gives an assured second-strike capability.
- Credible minimum deterrence: survivability, not numbers, makes deterrence credible; the triad lets India keep a modest arsenal while signalling assured retaliation.
- Supporting elements: Nuclear Command Authority, Strategic Forces Command, MIRV capability (Agni-V, 2024) and ballistic missile defence.
- Challenges: cost of submarines, longer-range sea-based missiles, secure communication with submerged submarines.
Conclusion: The triad, especially its sea-based leg, turns India’s no-first-use doctrine from a declaration into a credible posture.