Q60. If a major solar storm reaches Earth, which effects are possible?
1. GPS failure
2. Equatorial tsunamis
3. Damage to power grids
4. Strong auroras
5. Planet-wide forest fires
6. Disturbed satellite orbits
7. Interrupted polar shortwave aircraft radio.
[UPSC CSE Prelims 2022]
(A) 1, 2, 4 and 5 only
(B) 2, 3, 5, 6 and 7 only
(C) 1, 3, 4, 6 and 7 only
(D) All seven
Answer: (C) 1, 3, 4, 6 and 7 only
Explanation: Geomagnetic storms can induce grid currents, disrupt GPS and radio signals, alter atmospheric drag on satellites and produce auroras. They do not directly trigger tsunamis or widespread forest fires. Statements 1, 3, 4, 6 and 7 are therefore valid.
Q59. Which statement about GPS is NOT correct?
[UPSC NDA (I) 2022 – General Ability Test]
(A) It relies on a network of orbiting satellites
(B) It uses positioning calculations based on satellite signals
(C) Receivers can report latitude, longitude and altitude
(D) It supplies information exclusively for military operations
Answer: (D) It supplies information exclusively for military operations
Explanation: GPS began as a US military system but is used extensively by civilian receivers worldwide. A GPS receiver derives position from the timing of signals transmitted by several satellites; ordinary applications include mapping, transport and emergency response.
Q58. The thick yellowish clouds in Venus’s atmosphere are mainly associated with which substance?
[UPSC CDS (II) 2022 – General Knowledge]
(A) Chlorine
(B) Sulphuric acid
(C) Nitric acid
(D) Bromine
Answer: (B) Sulphuric acid
Explanation: Venus’s global clouds consist largely of sulphuric-acid droplets. They reflect much incoming sunlight, while the thick carbon-dioxide atmosphere traps heat and produces an intense greenhouse effect. The surface remains extremely hot beneath these clouds.
Q57. Which planet had the greatest number of known natural satellites among these options at the time of the paper?
[UPSC CDS (II) 2022 – General Knowledge]
(A) Mars
(B) Neptune
(C) Jupiter
(D) Saturn
Answer: (D) Saturn
Explanation: Saturn was the answer in the examination’s contemporary moon counts. Discovery totals change as astronomers confirm additional small satellites, so such questions must be understood using the tally known when the examination was held.
Q56. Why do planets generally not twinkle in the same way as distant stars?
[RRB Group D, 18 August 2022, Shift 3]
(A) They scatter less light
(B) They act as extended light sources
(C) They behave as ideal point sources
(D) They scatter more light
Answer: (B) They act as extended light sources
Explanation: Planets appear as tiny discs rather than ideal points. Atmospheric refraction fluctuations from different parts of each disc average out, reducing brightness scintillation. Distant stars appear almost point-like, so their light varies more noticeably through turbulent air.
Q55. Which planet has the highest average density among Mercury, Venus, Jupiter and Earth?
[UPSC NDA (I) 2022 – General Ability Test]
(A) Mercury
(B) Venus
(C) Jupiter
(D) Earth
Answer: (D) Earth
Explanation: Earth’s relatively large iron core contributes to its high mean density of about 5.51 grams per cubic centimetre. Venus and Mercury are also rocky and dense, while Jupiter has a much lower average density due to its gaseous composition.
Q54. Why are astronomical distances often measured in light-years?
[UPSC CSE Prelims 2021]
(A) Distances between stars never change
(B) Gravity between stars never changes
(C) Light always travels in a straight line
(D) The speed of light in vacuum is constant
Answer: (D) The speed of light in vacuum is constant
Explanation: A light-year is a unit of length: the distance light travels through vacuum in one Julian year, approximately 9.46 trillion kilometres. The fixed speed of light makes it a convenient standard for communicating very large stellar distances.
Q53. Which is NOT part of our Solar System?
[RRB NTPC CBT I, 23 July 2021, Shift 2]
(A) Europa
(B) Moon
(C) Pole Star
(D) Sun
Answer: (C) Pole Star
Explanation: Polaris, the Pole Star, is a distant stellar system rather than a body orbiting our Sun. Europa is a moon of Jupiter, the Moon orbits Earth, and the Sun is the Solar System’s central star.
Q52. Which is the nearest star to Earth?
[RRB NTPC CBT I, 5 April 2021, Shift 1]
(A) Altair
(B) Sun
(C) Vega
(D) Moon
Answer: (B) Sun
Explanation: The Sun is Earth’s nearest star and provides the energy sustaining life. The Moon is a natural satellite, not a star. Stars such as Altair and Vega are many light-years farther away than the Sun.
Q51. Which theory best explains the origin of the Universe?
[UPSC NDA (I) 2021 – General Ability Test]
(A) Nebular hypothesis
(B) Binary theory
(C) Big Bang theory
(D) Planetesimal hypothesis
Answer: (C) Big Bang theory
Explanation: The Big Bang model describes the early hot, dense universe and its subsequent expansion. The nebular and planetesimal hypotheses deal with planetary-system formation, not the initial history of the universe as a whole.
