All Free Everyday Science MCQs with Answers

221. How long does it take for the moon to orbit the earth once?

• A. 26.3 days
• B. 27.3 days
• C. 28.3 days
• D. 30.3 days

Explanation: The Moon takes about 27.3 days to complete one orbit relative to the stars, called its sidereal period. Its cycle from one new moon to the next is longer, about 29.5 days, because Earth is also moving around the Sun.

222. The distance b/w Earth and Moon is___________?

• A. 3,50,000km
• B. 3,60,100km
• C. 3,72,000km
• D. 3,84,400km

Explanation: The average distance from Earth to the Moon is approximately 384,400 km. Because the orbit is elliptical, the actual distance varies during the month.

223. The Time taken for sunlight to reach the Earth is___________?

• A. 700 sec
• B. 8hrs 20 mins
• C. 8 mins 20 sec
• D. 8 mins

Explanation: Sunlight travels about 150 million kilometres to Earth at roughly 300,000 km per second. The resulting travel time is approximately 500 seconds, or 8 minutes 20 seconds.

224. One Astronomical unit is equal to how much Km in whole numbers?

• A. 160 million km
• B. 140 million km
• C. 150 million km
• D. 130 million km

Explanation: One astronomical unit is the average Earth-Sun distance, about 149.6 million kilometres. Rounded to a whole number in the options, this is 150 million km.

225. Approximate age of milky-way is ________?

• A. 16.5 billion years
• B. 15.5 billion years
• C. 13.5 billion years
• D. 14.5 billion years

Explanation: The Milky Way began forming roughly 13.5 to 13.6 billion years ago, close to the age of the universe. Thus 13.5 billion years is the best listed approximation.

226. Approximate age of earth is ________?

• A. 4.14 billion years
• B. 4.64 billion years
• C. 4.54 billion years
• D. 4.34 billion years

Explanation: Radiometric dating of meteorites and the oldest Earth materials places Earth’s age at about 4.54 billion years. The other values differ noticeably from this accepted estimate.

227. Approximate age of sun is _________?

• A. 4.4 billion years
• B. 4.5 billion years
• C. 4.6 billion years
• D. 4.7 billion years

Explanation: The Sun is about 4.6 billion years old, based on the ages of meteorites and the oldest Solar System material. It is currently roughly halfway through its expected 10-billion-year main-sequence lifetime.

228. Which gas was discovered on the sun about 151 years ago during total solar eclipse?

• A. Hydrogen
• B. Helium
• C. Nitrogen
• D. Flourine

Explanation: Helium was first identified in the Sun’s spectrum during the 1868 total solar eclipse, before it was found on Earth. Its name comes from Helios, the Greek Sun god.

229. Largest moon in our solar system is ________?

• A. Deimos
• B. Ganymede
• C. Phobos
• D. Arche

Explanation: Ganymede, one of Jupiter’s moons, is the largest moon in the Solar System and is even larger in diameter than Mercury. Phobos and Deimos are small moons of Mars.

230. what are stars mainly made of ?

• A. Balls of gass
• B. Rock
• C. Ice
• D. Light

Explanation: Stars are enormous spheres of extremely hot gas, mainly hydrogen and helium. Their light and heat come from nuclear fusion in their interiors, not from being made of light.