Free Astronomy and Space MCQs with Answers

201. The Sun produces most of its energy by_____________?

• A. Nuclear fusion
• B. nuclear fission
• C. Burning hydrogen
• D. None of these

Explanation: The Sun's core produces energy through nuclear fusion, mainly joining hydrogen nuclei to form helium and releasing energy. This is not ordinary burning or nuclear fission.

202. Primary cosmic rays are composed largely of very fast__________?

• A. Protons
• B. Neutrons
• C. Electrons
• D. Gamma rays

Explanation: Primary cosmic rays consist largely of extremely fast protons, with smaller amounts of heavier atomic nuclei and electrons. Gamma rays are electromagnetic radiation rather than the main composition of primary cosmic rays.

203. The time taken by Sun to revolve around the center of our galaxy is___________?

• A. 150 million years
• B. 250 million years
• C. 300 millon years
• D. 350 millon years

Explanation: The Solar System takes roughly 225 to 250 million years to complete one orbit around the centre of the Milky Way, commonly called a galactic year. Therefore, 250 million years is the closest option.

204. The Sun is at an average distance of about________ million kilometers away from Earth?

• A. 100 million
• B. 150 million
• C. 200 million
• D. 250 million

Explanation: Earth's average distance from the Sun is about 149.6 million kilometres, commonly rounded to 150 million kilometres. This distance is also called one astronomical unit.

205. Which rays are trapped in our galaxy by magnetic waves?

• A. Alpha rays
• B. Gamma rays
• C. Cosmic rays
• D. None of these

Explanation: Cosmic rays are high-energy particles that are largely confined within the Milky Way by its magnetic fields. Alpha and gamma rays are types of radiation, but the standard term for these trapped high-energy particles is cosmic rays.

206. According to Einsteins general theory of relativity the universe:________________?

• A. Must be expanding
• B. Must be contracting
• C. Must be either expanding or contracting
• D. Must be neither expanding nor contracting

Explanation: In the standard interpretation of general relativity, a universe without a stable static state must undergo expansion or contraction. Observations show that our universe is expanding, but the option describes the theoretical alternatives.

207. There is no connection of supernova explosion with___________?

• A. Cosmic rays
• B. Pulsars
• C. The formation of heavy elements
• D. Quasars

Explanation: Supernovae are linked with cosmic rays, pulsars and the creation or dispersal of many heavy elements. Quasars are extremely luminous active galactic nuclei and are not a direct consequence of supernova explosions.

208. The Temperature of the surface of Sun is_______?

• A. 5,778 Kelvin
• B. 6,778 Kelvin
• C. 7,778 Kelvin
• D. 9,778 Kelvin

Explanation: The Sun's visible surface, or photosphere, has an effective temperature of about 5,778 K, often rounded to 5,800 K. Its core is vastly hotter, so the question's surface specification is important.

209. Mass of Earth is___________?

• A. 5.972 × 1024 kg.
• B. 6.972 × 1024 kg
• C. 7.972 × 1024 kg
• D. 8.972 × 1024 kg

Explanation: Earth's mass is approximately 5.972 × 10²⁴ kilograms, determined from its gravitational effect and standard gravitational constant. The other figures differ substantially from the accepted value.

210. When a single month has two full moons, the second moon is called________?

• A. Super moon
• B. Blue moon
• C. Super blue moon
• D. Red moon

Explanation: When two full moons occur in the same calendar month, the second is traditionally called a blue moon. The name refers to the calendar occurrence, not to the Moon actually appearing blue.