📘 IAS Prelims 2025 — GS-I Q.42 | Classroom Explanation

(Science & Technology | Current Affairs)

📌 Question

Q.42) With reference to Unmanned Aerial Vehicles (UAVs), consider the following statements:

I. All types of UAVs can do vertical landing.
II. All types of UAVs can do automated hovering.
III. All types of UAVs can use battery only as a source of power supply.

How many of the statements given above are correct?

(a) Only one
(b) Only two
(c) All the three
(d) None

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✅ Correct Answer: (d)

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🧑‍🏫 Classroom Explanation

This question tests basic UAV typology and key flight capabilities: VTOL, hover, and power systems. UPSC often uses “All types…” to plant a trap.

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🔍 Key Concept: UAV Types (Why “All types” is risky)

Common UAV categories include:
• Multi-rotor (quadcopter, hexacopter)
• Fixed-wing UAVs
• Hybrid VTOL (fixed-wing + vertical lift)
• High-endurance / military UAVs (often fixed-wing)

Each category has different capabilities.

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🔍 Statement-wise Analysis

❌ Statement I: Incorrect

• Not all UAVs can do vertical landing.
• Fixed-wing UAVs generally require:

• Runway / catapult launch and runway landing, or
• Net / belly landing methods

• Only VTOL-capable designs (multi-rotor, hybrid VTOL) can do true vertical landing.

➡️ Statement I is incorrect.

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❌ Statement II: Incorrect

• Hovering requires generating lift without forward motion.
• Multi-rotor UAVs can hover.
• Fixed-wing UAVs cannot hover because they need airflow over wings to generate lift.

“Automated hovering” is possible only where hovering is possible in the first place.

➡️ Statement II is incorrect.

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❌ Statement III: Incorrect

• UAVs do not universally rely only on batteries.
• Power sources include:

• Batteries (common in small multi-rotors)
• Internal combustion engines (petrol/diesel)
• Hybrid systems
• Fuel cells (in some advanced UAVs)

Long-range and high-endurance UAVs often avoid battery-only due to energy density limits.

➡️ Statement III is incorrect.

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🧮 Logical Counting (UPSC Style)

• I → Incorrect ❌
• II → Incorrect ❌
• III → Incorrect ❌

➡️ Number of correct statements = 0

➡️ Correct option: (d) None

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🎯 Final Answer

✅ Correct Answer: (d)

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📦 Info Box — High-Value UPSC Add-ons

🧠 Quick 3-Word Memory Rule

Hover = Rotor, Range = Wing, Endurance = Fuel

⚠️ UPSC Trap Alert

• Statements beginning with “All types…” are often false in tech classification questions.
• Fixed-wing UAVs:

• Great for range/endurance
• Weak for hover/VTOL

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📍 GS Mapping

GS Paper I (Prelims)
Theme: Science & Technology
Topic: UAV Basics, Emerging Tech
Nature: Conceptual + Application-based

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