Level 1
Astronomy MCQs set 2 for OTS Health Department Posts Everyday Science — 20 solved questions.
Q1. The planet which revolves slowly around the Sun is ____?
Answer: Neptune
Explanation: Neptune has the longest orbital period of any planet at approximately 164.8 Earth years, because it is farthest from the Sun and travels the longest orbital path at the slowest speed.
Q2. Which planet is called the "lopsided planet" because of its extreme axial tilt?
Answer: Uranus
Explanation: Uranus has an axial tilt of about 97.77°, meaning it effectively rotates on its side; this extreme tilt causes it to be called the "lopsided" or "tilted" planet.
Q3. Which of the following planets has no moon?
Answer: Mercury
Explanation: Mercury has no moons; it has no natural satellites due to its small size, weak gravity, and proximity to the Sun's gravitational dominance.
Q4. The sunlight can reach a depth of _____ meters in the ocean.
Answer: 200m
Explanation: The photic (sunlight) zone of the ocean extends to approximately 200 meters depth; below this, insufficient light penetrates for photosynthesis to occur.
Q5. Which gas present in the Earth's atmosphere can absorb solar ultraviolet radiation?
Answer: Ozone
Explanation: The ozone (O₃) layer in the stratosphere absorbs most of the Sun's harmful ultraviolet (UV-B and UV-C) radiation, protecting life on Earth from DNA damage and skin cancer.
Q6. Which is the hottest planet in our solar system?
Answer: Venus
Explanation: Venus is the hottest planet with surface temperatures averaging ~465°C due to an extreme greenhouse effect from its dense CO₂ atmosphere, even though Mercury is closer to the Sun.
Q7. Which of the following is the unit used to measure the distance between planets and stars?
Answer: Light year
Explanation: The light-year is the standard unit for measuring astronomical distances between stars and galaxies, equal to about 9.46 × 10¹² km - the distance light travels in one year.
Q8. Which of the following planets is known as the "morning star" or "evening star"?
Answer: Venus
Explanation: Venus appears as a bright "star" in the sky just before sunrise or just after sunset due to its orbit being closer to the Sun than Earth's, earning it the names "morning star" and "evening star."
Q9. Stars produce heat and light energy due to the fusion of ______.
Answer: hydrogen
Explanation: Stars generate energy through nuclear fusion, primarily the proton-proton chain in which hydrogen nuclei fuse to form helium, releasing enormous amounts of energy as per E = mc².
Q10. The most abundant gas in the earth's atmosphere is:
Answer: Nitrogen
Explanation: Nitrogen is the scientifically accurate choice. The concept tested here is core everyday science for MDCAT, ECAT, and general ability papers.
Q11. The hottest & the brightest planet of the solar system is:
Answer: Venus
Explanation: Venus is both the hottest planet (average surface temp ~465°C due to greenhouse effect) and the brightest object in the night sky after the Moon.
Q12. The sky appears blue because the Earth's atmosphere:
Answer: Scatters blue light more than other colors
Explanation: Rayleigh scattering causes shorter wavelength blue light to scatter much more than longer wavelengths when sunlight interacts with gas molecules in the atmosphere.
Q13. Hydrogen in the Sun is 73 percent, whereas 25 percent is:
Answer: Helium
Explanation: Helium is the scientifically accurate choice. The concept tested here is core everyday science for MDCAT, ECAT, and general ability papers.
Q14. When a ray of sunlight enters a dark room, its straight path becomes visible because of dust particles in the air. This is because light is:
Answer: Scattered
Explanation: Dust particles scatter the light beam via the Tyndall effect, making the path of light visible - this is an example of light scattering by colloidal particles.
Q15. The severity of the 2005 earthquake in Pakistan on the Richter scale was:
Answer: 7.6
Explanation: The 2005 Kashmir earthquake that struck northern Pakistan and Azad Kashmir on October 8 registered a magnitude of 7.6 on the Richter scale.
Q16. The production of rubber trees is better adapted to areas where the climate is:
Answer: Warm and humid
Explanation: Rubber trees (Hevea brasiliensis) are native to the Amazon basin and thrive in warm (25-35°C), humid tropical climates with high annual rainfall.
Q17. Sunlight can reach a depth of ____ meters in the ocean.
Answer: 200 m
Explanation: The photic zone extends to approximately 200 meters depth in clear ocean water, where sufficient sunlight penetrates for photosynthesis.
Q18. The outer surface of the sun is called the:
Answer: Photosphere
Explanation: The photosphere is the visible outer surface (layer) of the Sun from which light is emitted; the corona is the outer atmosphere visible only during a solar eclipse.
Q19. The ozone layer prevents ____ radiation from entering the atmosphere.
Answer: Ultraviolet
Explanation: The stratospheric ozone layer absorbs 97-99% of the Sun's harmful ultraviolet (UV-B and UV-C) radiation, preventing it from reaching Earth's surface.
Q20. The time taken for sunlight to reach the Earth is:
Answer: 8 minutes 20 seconds
Explanation: The Sun is approximately 150 million km from Earth, and light travels at 300,000 km/s; 150,000,000 ÷ 300,000 = 500 seconds = 8 minutes 20 seconds.