The terms ‘Event Horizon’, ‘Singularity’, ‘String Theory’ and ‘Standard Model’ are sometimes seen in the news in the context of
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Answer: A. An event horizon is the boundary of a black hole. A singularity is the point of infinite density at its centre or at the Big Bang. String theory and the Standard Model are physics theories of fundamental particles and forces. All four are used to observe and understand the universe. They were in the news after the 2016 gravitational wave detection. So the answer is A.
Watch for: Watch for the word 'origin' in option D. The Big Bang is about the origin of the universe, not of living things.
Why the other options are wrong
- B. Wrong because eclipses are explained by simple Sun-Earth-Moon geometry, not these concepts.
- C. Wrong because satellite orbits use Newtonian mechanics, not black-hole or particle physics.
- D. Wrong because the origin of life is a question for biology, not these physics terms.
Source to check: NCERT Class 11 Physics Part I, Chapter 1 'Physical World' (fundamental forces); NASA Science, 'Black Holes' (science.nasa.gov); CERN, 'The Standard Model' (home.cern)
Answer from the official UPSC key. Written and fact-checked by AI against the official key. Spotted a mistake? Report it.