Q70. Which statements about planets are correct?
1. Mercury has no atmosphere.
2. Venus has two moons.
3. Jupiter has no solid land surface.
4. Saturn’s rings consist of ice and dust.
[UPSC CDS (II) 2023 – General Knowledge]
(A) 1 and 2 only
(B) 3 and 4 only
(C) 1, 2 and 3
(D) 1, 3 and 4
Answer: (B) 3 and 4 only
Explanation: Venus has no natural moon, so statement 2 is false. Mercury possesses an extremely thin exosphere rather than a substantial atmosphere. Jupiter is a gas giant without a conventional solid surface, and Saturn’s rings contain ice particles and dust.
Q69. Approximately what percentage of carbon dioxide is present in the atmospheres of Venus and Mars?
[UPSC CDS (II) 2023 – General Knowledge]
(A) 45–47%
(B) 52–55%
(C) 74–77%
(D) 95–97%
Answer: (D) 95–97%
Explanation: Both Venus and Mars have atmospheres dominated by carbon dioxide, with shares close to 95–97 percent. Their atmospheric pressures differ enormously: Venus has a dense atmosphere causing extreme greenhouse warming, while Mars has a much thinner atmosphere.
Q68. Which Indian musician had a minor planet between Mars and Jupiter named in his honour by the International Astronomical Union?
[SSC CGL Tier I, 24 July 2023, Shift 1]
(A) Pandit Hariprasad Chaurasia
(B) Pandit Ravi Shankar
(C) Ustad Zakir Hussain
(D) Pandit Jasraj
Answer: (D) Pandit Jasraj
Explanation: Minor planet 300128 Panditjasraj was named in honour of the renowned Hindustani classical vocalist Pandit Jasraj. Minor planets, many of them in the asteroid belt, receive formally approved names through international astronomical naming procedures.
Q67. Which is the largest planet in the Solar System?
[SSC MTS 2022, held 13 June 2023, Shift 1]
(A) Neptune
(B) Earth
(C) Uranus
(D) Jupiter
Answer: (D) Jupiter
Explanation: Jupiter is the largest planet by both mass and diameter. It is predominantly hydrogen and helium, possesses the Great Red Spot, and has a powerful magnetosphere. Its large size distinguishes it from other gas and ice giant planets.
Q66. Which is the smallest of the eight planets in the Solar System?
[SSC MTS 2022, held 20 June 2023, Shift 3]
(A) Earth
(B) Mars
(C) Mercury
(D) Venus
Answer: (C) Mercury
Explanation: Mercury is the smallest recognised planet and the closest to the Sun. Pluto is classified as a dwarf planet, not one of the eight major planets. Mercury has a rocky surface, a large metallic core, and virtually no substantial atmosphere.
Q65. Which planet is NOT among the four inner planets?
[SSC CHSL Tier I 2022, held 13 March 2023, Shift 4]
(A) Mars
(B) Venus
(C) Mercury
(D) Jupiter
Answer: (D) Jupiter
Explanation: The four inner, terrestrial planets are Mercury, Venus, Earth and Mars. Jupiter lies beyond the asteroid belt and is a gas giant. Inner planets are smaller and predominantly rocky compared with the outer giant planets.
Q64. Which hypothesis is most widely accepted for the origin of the Solar System?
[SSC CPO Paper I, 3 October 2023, Shift 1]
(A) Nebular hypothesis
(B) Gas hypothesis
(C) Solar hypothesis
(D) Cloud hypothesis
Answer: (A) Nebular hypothesis
Explanation: The modern solar nebular model explains the Sun and planets forming from the gravitational collapse of a rotating cloud of gas and dust. A flattened circumstellar disc supplied material that accreted into planetesimals and eventually planets.
Q63. Which recent ISRO scientific mission was launched to undertake a comprehensive study of the Sun?
[MPPSC State Services Prelims, 17 December 2023]
(A) Aditya-L1
(B) Bhaskara-L2
(C) Solar Mission-L1
(D) Solar Orbiter
Answer: (A) Aditya-L1
Explanation: Aditya-L1 is India’s first dedicated solar observatory mission, launched in September 2023. Its instruments study the Sun’s atmosphere, particle environment and magnetic activity from a halo orbit around the Sun–Earth L1 region.
Q62. Which launch vehicle carried the Chandrayaan-3 mission?
[WBCS Main Examination 2023 – Paper IV]
(A) GSLV
(B) LVSM
(C) GSLV Mk III (LVM3)
(D) PSLV
Answer: (C) GSLV Mk III (LVM3)
Explanation: Chandrayaan-3 launched on 14 July 2023 aboard LVM3-M4, the vehicle formerly designated GSLV Mk III. ISRO’s official mission record confirms this. Some commercial answer keys list generic GSLV, but the technically precise choice is option C.
Q61. What was the last PSLV mission launched by ISRO during calendar year 2022?
[CGPSC Prelims 2023 – General Studies]
(A) PSLV-C54
(B) PSLV-C53
(C) PSLV-C52
(D) PSLV-C51
Answer: (A) PSLV-C54
Explanation: PSLV-C54 lifted off on 26 November 2022 carrying EOS-06, an ocean-observation spacecraft, and several co-passenger satellites. It was the final PSLV launch that calendar year, following the earlier C52 and C53 missions.
