Solar System, Stars, Galaxies and the Universe

Attempt the quiz above first, then review every question with its correct answer and a short explanation below.

1. Q1.Which is the largest planet of the solar system?

   • A.Saturn
   • B.Jupiter✓ Correct Answer
   • C.Neptune
   • D.Earth

   Explanation: Jupiter's mass is more than twice that of all other planets combined.

2. Q2.The nearest star to the Earth is:

   • A.Proxima Centauri
   • B.Sirius
   • C.the Sun✓ Correct Answer
   • D.Polaris

   Explanation: Proxima Centauri is the nearest star after the Sun.

3. Q3.The galaxy in which our solar system lies is the:

   • A.Milky Way✓ Correct Answer
   • B.Andromeda
   • C.Triangulum
   • D.Whirlpool

   Explanation: It is a spiral galaxy.

4. Q4.Which planet is nearest to the Sun?

   • A.Venus
   • B.Mercury✓ Correct Answer
   • C.Mars
   • D.Earth

   Explanation: Mercury is also the smallest planet.

5. Q5.Which planet is known as the Red Planet?

   • A.Jupiter
   • B.Venus
   • C.Mercury
   • D.Mars✓ Correct Answer

   Explanation: Iron oxide on its surface gives the reddish colour.

6. Q6.The natural satellite of the Earth is the:

   • A.Phobos
   • B.Titan
   • C.Europa
   • D.Moon✓ Correct Answer

   Explanation: The Moon takes about 27 days to orbit the Earth.

7. Q7.The Big Bang theory explains the:

   • A.origin of life on Earth
   • B.formation of the Moon only
   • C.origin and expansion of the universe✓ Correct Answer
   • D.cause of tides

   Explanation: The universe began about 13.8 billion years ago from a hot dense state.

8. Q8.Sunlight takes about how long to reach the Earth?

   • A.8 seconds
   • B.8 minutes✓ Correct Answer
   • C.8 hours
   • D.1 second

   Explanation: The distance is about 150 million km.

9. Q9.Light from the Moon takes about how long to reach the Earth?

   • A.13 seconds
   • B.8 minutes
   • C.1 hour
   • D.1.3 seconds✓ Correct Answer

   Explanation: The Moon is about 3.84 lakh km away.

10. Q10.Titan is the largest moon of:

    • A.Jupiter
    • B.Saturn✓ Correct Answer
    • C.Mars
    • D.Neptune

    Explanation: Titan has a dense atmosphere.

11. Q11.The hottest planet of the solar system is:

    • A.Mercury
    • B.Mars
    • C.Venus✓ Correct Answer
    • D.Jupiter

    Explanation: Its thick carbon dioxide atmosphere causes a runaway greenhouse effect.

12. Q12.The Chandrasekhar limit is about:

    • A.0.1 solar mass
    • B.14 solar masses
    • C.1.4 solar masses✓ Correct Answer
    • D.100 solar masses

    Explanation: A white dwarf heavier than this collapses further.

13. Q13.In 2006 Pluto was reclassified by the IAU as a:

    • A.comet
    • B.moon of Neptune
    • C.asteroid
    • D.dwarf planet✓ Correct Answer

    Explanation: It did not clear the neighbourhood around its orbit.

14. Q14.The asteroid belt lies between the orbits of:

    • A.Earth and Mars
    • B.Mars and Jupiter✓ Correct Answer
    • C.Jupiter and Saturn
    • D.Venus and Earth

    Explanation: Ceres, the largest object there, is a dwarf planet.

15. Q15.A light-year is approximately:

    • A.9.46 × 10^6 km
    • B.3 × 10^8 km
    • C.1.5 × 10^8 km
    • D.9.46 × 10^12 km✓ Correct Answer

    Explanation: It is the distance light travels in a year.

16. Q16.The Sun is classified as a:

    • A.main-sequence star✓ Correct Answer
    • B.red giant
    • C.white dwarf
    • D.neutron star

    Explanation: It is fusing hydrogen in its core.

17. Q17.Hubble's law says that distant galaxies recede with a speed that is:

    • A.proportional to their distance✓ Correct Answer
    • B.inversely proportional to distance
    • C.independent of distance
    • D.always zero

    Explanation: This is evidence of an expanding universe.

18. Q18.A black hole is a region from which:

    • A.even light cannot escape✓ Correct Answer
    • B.only sound cannot escape
    • C.only matter can escape
    • D.everything escapes freely

    Explanation: Its escape velocity exceeds the speed of light.

19. Q19.The Sun produces its energy mainly by:

    • A.nuclear fusion of hydrogen into helium✓ Correct Answer
    • B.nuclear fission of uranium
    • C.burning of coal
    • D.chemical reactions

    Explanation: Fusion converts a small mass into large energy as E = mc².

20. Q20.Which planet has the shortest rotation period (shortest day)?

    • A.Mercury
    • B.Earth
    • C.Jupiter✓ Correct Answer
    • D.Venus

    Explanation: Jupiter rotates once in about 10 hours.