All Free Everyday Science MCQs with Answers

241. Hailey's comet is visible after every_________?

• A. 84 years
• B. 76 years
• C. 1000 years
• D. 365 years

Explanation: Halley's Comet returns approximately every 75 to 76 years because that is its orbital period around the Sun. Its recorded returns are therefore measured in decades, not centuries.

242. Which of the followong spacecrsft enabled man to step on the moon first?

• A. Spuntnik I
• B. Luna II
• C. Vostok I
• D. Apollo XI

Explanation: Apollo 11 carried Neil Armstrong and Buzz Aldrin to the lunar surface in 1969, making them the first humans to walk on the Moon. Sputnik I was a satellite, while Luna II was an unmanned probe and Vostok I carried the first human into space.

243. Among the planets of the Solar system the position of the Earth from the Sun is:_________?

• A. Second
• B. Third
• C. Fourth
• D. Sixth

Explanation: Earth is the third planet from the Sun, after Mercury and Venus. Its orbital position is distinct from its size or distance from other planets.

244. Most important effect of the moon on earth is that it___________?

• A. Causes weather change
• B. Causes earthquakes
• C. Causes solar and lunar eclipse
• D. Effects tides of the ocean

Explanation: The Moon's gravitational pull, together with the Sun's influence, produces the regular rise and fall of ocean tides. Weather and earthquakes are not the Moon's most important established effect on Earth.

245. The Lunar eclipse occurs when:

• A. Moon is b/w the earth and the sun
• B. Earth is b/w the sun and the moon
• C. Sun is b/w the earth and the moon
• D. Earth is at right angles to the direction of the sun and the moon

Explanation: A lunar eclipse occurs when Earth comes between the Sun and the Moon, causing Earth's shadow to fall on the Moon. The opposite arrangement, with the Moon between Earth and the Sun, produces a solar eclipse.

246. Which is the nearest star to our sun?

• A. Proxima Centurai
• B. Alpha Scorpii
• C. Beta Orionis
• D. Vega

Explanation: Proxima Centauri is the nearest known star to the Sun, at about 4.24 light-years away. The other listed stars are much farther from our solar system.

247. Who was the first to measure the earth's radius

• A. Galileo
• B. Copernicus
• C. Ptolemy
• D. Eratosthenes

Explanation: The Greek scholar Eratosthenes estimated Earth's size by comparing noon shadows at two locations and using the angle difference to calculate its circumference and radius. Galileo, Copernicus, and Ptolemy are associated with other major developments in astronomy.

248. Which of the following is the largest planet?

• A. Neptune
• B. Jupiter
• C. Saturn
• D. Mars

Explanation: Jupiter is the largest planet in the solar system, both in diameter and mass. Saturn and Neptune are also giant planets but are smaller than Jupiter.

249. Which of the following planets has the smallest diameters_____?

• A. Mercury
• B. Marx
• C. Pluto
• D. Venus

Explanation: Mercury is the smallest of the eight officially recognised planets. Pluto is smaller, but it is classified as a dwarf planet rather than a planet, so Mercury is the intended answer.

250. Which of the following planets is fastest rotating planet?

• A. Mercury
• B. Marx
• C. Jupiter
• D. Venus

Explanation: Jupiter rotates once in about 10 hours, making it the fastest-rotating planet in the solar system. The option printed as “Marx” presumably refers to Mars, which rotates much more slowly.