CDS (II) 2025 · General Knowledge
A full General Knowledge paper in the UPSC CDS pattern: 120 questions in 2 hours, with a third of the question's marks deducted for every wrong answer. Physics, Chemistry, Biology, defence and security, History, Geography, Polity, Economy and current events.
120questions
100marks
2 hoursno calculator
40/60/20easy / medium / hard
Topics in this paper
General Knowledge · 120 questions
- Polity12
- Economy10
- Indian geography9
- World geography7
- Current events6
- Ancient India5
- Modern India5
- Sports4
- Cell biology3
- Security forces3
- Awards3
- Medieval India3
- Freedom struggle3
- Gravitation2
Sample question from this paper
Atomic physics · medium
In Rutherford's alpha-particle scattering experiment, the observation that a very few alpha particles were deflected through large angles led to the conclusion that
- A. electrons are embedded uniformly in a positive sphere
- B. the atom is a solid sphere of uniform density
- C. the atom has a small, dense, positively charged nucleus
- D. electrons move in orbits of fixed energy
Show answer and solution
Answer: C
Most alpha particles passed straight through the gold foil, so most of the atom is empty space. The few that rebounded must have met a tiny, heavy, positively charged centre, the nucleus. Uniform positive spheres were the idea of Thomson's model, and fixed energy orbits come from Bohr's later model.
Most alpha particles passed straight through the gold foil, so most of the atom is empty space. The few that rebounded must have met a tiny, heavy, positively charged centre, the nucleus. Uniform positive spheres were the idea of Thomson's model, and fixed energy orbits come from Bohr's later model.