All Free Everyday Science MCQs with Answers

141. The time in which Earth completes its revolution around the Sun is________?

• A. 365.25 days
• B. 340 days
• C. 325 days
• D. 360 days

Explanation: Earth takes about 365.25 days to complete one revolution around the Sun, with the extra quarter day accounted for by leap years. This is the basis of the civil year.

142. Which of the following is called as Blue planet?

• A. Mercury
• B. Earth
• C. Venus
• D. Neptune

Explanation: Earth is called the Blue Planet because oceans cover most of its surface and make it appear blue from space. Neptune also looks blue, but Earth's standard nickname is being tested here.

143. The movement of earth around sun brings ________?

• A. Tornadoes
• B. Rainfall
• C. Seasons
• D. Earthquakes

Explanation: Earth's revolution around the Sun, combined with the tilt of its rotational axis, produces the seasons. Revolution alone without axial tilt would not create the familiar seasonal pattern.

144. The radiant energy having lowest energy is?

• A. gamma rays
• B. UV rays
• C. visible light
• D. Radio waves

Explanation: Among the listed forms, radio waves have the lowest frequency and therefore the lowest photon energy, since energy is proportional to frequency. Gamma rays have the highest energy, followed by ultraviolet and visible light.

145. Who enunciated the laws of planetary motion?

• A. Nicolaus Copernicus
• B. Johannes Kepler
• C. Isaac Newton
• D. Galile

Explanation: Johannes Kepler formulated the three laws describing planetary orbits, orbital speeds and periods. Copernicus proposed the heliocentric model, while Newton later explained Kepler’s laws through gravity.

146. Galileo was an Italian astronomer who _________?

• A. Developed the telescope
• B. Discovered four satellites of Jupiter
• C. Discovered that the movement of pendulum produces a regular time measurement
• D. All of the above

Explanation: Galileo improved the telescope for astronomy, discovered four large moons of Jupiter, and studied the regular timing of a pendulum's swing. In the usual school-level wording, all three statements are credited to him.

147. Who was the first to measure the earth's circumference?

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

Explanation: Eratosthenes estimated Earth’s circumference by comparing the Sun’s shadow angles at two locations and using the distance between them. Galileo and Copernicus are associated mainly with astronomy and planetary motion, not this measurement.

148. The _____ is the largest natural source of light?

• A. Sun
• B. Moon
• C. Star
• D. None of these

Explanation: The Sun is a star and is by far the largest and most powerful natural source of light reaching Earth. The Moon mainly reflects sunlight rather than producing its own light.

149. In Astronomy, what are Pallas, Vesta and Davida?

• A. Stars
• B. Comets
• C. Asteroids
• D. None of these

Explanation: Pallas, Vesta and Davida are names of asteroids in the Solar System. Unlike comets, they are mainly rocky or metallic bodies and do not characteristically form bright tails near the Sun.

150. The period of revolution of a geostationary satellite is?

• A. 365 days
• B. 30 days
• C. 24 hours
• D. changing continuously

Explanation: A geostationary satellite must rotate once in the same time that Earth rotates, so it remains above the same point on the equator. This period is approximately 24 hours.