OTS Water & Sanitation Dept (WSSP / PHED) Everyday Science: Astronomy MCQs

Practice Astronomy MCQs for OTS Water & Sanitation Dept (WSSP / PHED) Everyday Science — topic-wise sets with solved answers.

OTS Water & Sanitation Dept (WSSP / PHED) Everyday Science: Astronomy MCQs — sample questions

  1. Question 1

    Q1. Which is the brightest planet in the solar system?

    • A) Mars
    • B) Venus
    • C) Jupiter
    • D) Mercury

    Answer: Venus

    Explanation: Venus is the brightest planet as seen from Earth due to its thick, highly reflective cloud cover that reflects about 70% of sunlight.

  2. Question 2

    Q2. In a typical H-R diagram, stars are graphed by which two characteristics?

    • A) Luminosity and distance
    • B) Distance and temperature
    • C) Size and distance
    • D) Temperature and Luminosity

    Answer: Temperature and Luminosity

    Explanation: The Hertzsprung-Russell (H-R) diagram plots stars according to their luminosity (absolute brightness) on the y-axis and surface temperature (spectral class) on the x-axis.

  3. Question 3

    Q3. How many planets are in our solar system:

    • A) 6
    • B) 7
    • C) 8
    • D) 9

    Answer: 8

    Explanation: Since Pluto was reclassified as a dwarf planet by the IAU in 2006, our solar system officially has eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

  4. Question 4

    Q4. Which gas in Chlorofluorocarbons damages the ozone layer most:

    • A) Chlorine
    • B) Fluorine
    • C) Ammonia
    • D) Bromine

    Answer: Chlorine

    Explanation: In CFCs, chlorine atoms are the primary ozone-depleting agents; a single chlorine atom can catalytically destroy thousands of ozone molecules in the stratosphere.

  5. Question 5

    Q5. The ozone layer is at a height of ____ kilometers from the surface of the Earth.

    • A) 20 to 30
    • B) 30 to 40
    • C) 40 to 50
    • D) 10 to 20

    Answer: 20 to 30

    Explanation: The ozone layer is concentrated in the stratosphere at altitudes of approximately 20 to 30 kilometers above Earth's surface, where it absorbs harmful UV-B and UV-C radiation.

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