All Free Everyday Science MCQs with Answers

271. Which one is the brightest star in the night sky?

• A. Betelgeuse
• B. Sirius
• C. Rigel
• D. Polaris

Explanation: Sirius is the brightest star in the night sky as seen from Earth, mainly because it is relatively close and intrinsically luminous. Betelgeuse and Rigel are bright but appear dimmer, while Polaris is much less bright.

272. The large dark patches on the Moon's surface are known as___________?

• A. Dark matter
• B. Maria, or seas, even though there is no water on the Moon
• C. Maria, or seas, because they are filled with water
• D. Moon spots

Explanation: The Moon’s dark plains are called maria, the Latin plural of mare, meaning seas. They were once mistakenly thought to contain water, but they are actually ancient basaltic lava plains.

273. What causes the Moon's phases?

• A. The Sun lights up only one half of the Moon and as the Moon orbits the Earth we can sometimes see the unlit side of the Moon.
• B. The Sun lights up only one half of the Moon and as the Sun orbits the Earth we can sometimes see the unlit side of the Moon.
• C. The Earth's shadow falls on the Moon, blocking the sunlight.
• D. The Moon's shadow falls on the Earth, blocking the sunlight.Physics

Explanation: The Sun always illuminates half of the Moon, but as the Moon orbits Earth, we see different portions of that lit half. Earth’s shadow causes a lunar eclipse, not the regular phases of the Moon.

274. What are the names of the two stars in the Big Dipper used to locate Polaris?

• A. The North Seekers
• B. The Pointer Stars
• C. The Pointer Sisters
• D. None of these

Explanation: The two stars at the outer edge of the Big Dipper’s bowl are called the Pointer Stars because a line through them points toward Polaris. The other names are not standard astronomical terms.

275. The Big Dipper is part of which constellation?

• A. Ursa Major
• B. Ursa Minor
• C. The Great Bear
• D. A. and C. above

Explanation: The Big Dipper is an asterism within Ursa Major, whose name means Great Bear. Therefore both options A and C describe it, making D correct.

276. The sun is made up of 99.9% of ________________ and ______________?

• A. Oxygen and Hydrogen
• B. Hydrogen and Sulfur
• C. Carbon and Silicon
• D. Hydrogen and Helium

Explanation: Hydrogen and helium together account for about 99.9% of the Sun’s mass, with hydrogen making up the larger share. The heavier elements are present only in small amounts.

277. Antares is of the largest known ___________?

• A. Quasars Star
• B. Pulsars Star
• C. White Dwarfs Star
• D. Red Super-giants Star

Explanation: Antares is a red supergiant, a very large, cool star nearing the later stages of stellar evolution. Its reddish appearance comes from its relatively low surface temperature.

278. This in-between phase of stellar nurseries and star formation in stellar evolution is when the gathered dust is still condensing to form a star.

• A. Alpha Stage
• B. Stellar Genesis
• C. Protostar
• D. Star of Adam

Explanation: A protostar forms when gravity causes a cloud of gas and dust to contract before sustained hydrogen fusion begins in its core. It is therefore an intermediate stage between a stellar nursery and a true star.

279. Particle clouds from where stars are formed are known as____________?

• A. Stellar nurseries
• B. Star clouds
• C. Event horizons
• D. Singularities

Explanation: Stellar nurseries are dense clouds of gas and dust where gravity gathers material to form new stars. Event horizons and singularities are associated with black holes, not star-forming clouds.

280. PSR J0108-1431 is the closest known ______________ to Earth?

• A. Black hole
• B. Red giant
• C. Quasar
• D. Pulsar

Explanation: PSR J0108-1431 is a pulsar, meaning a rapidly rotating neutron star that produces periodic radiation signals. It is noted as one of the nearest known pulsars to Earth.