ISSB - PAF Officer Selection General Knowledge: Science MCQs

Practice Science MCQs for ISSB - PAF Officer Selection General Knowledge — topic-wise sets with solved answers.

ISSB - PAF Officer Selection General Knowledge: Science MCQs — sample questions

  1. Question 1

    Q1. Which planet is known as the Red Planet?

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

    Answer: Mars

    Explanation: Mars appears red due to iron oxide (rust) on its surface. Venus is the morning/evening star; Jupiter and Saturn are gas giants.

  2. Question 2

    Q2. Which gas is most abundant in Earth's atmosphere?

    • A) Oxygen
    • B) Carbon dioxide
    • C) Nitrogen
    • D) Hydrogen

    Answer: Nitrogen

    Explanation: Nitrogen ≈ 78%, Oxygen ≈ 21%. Students often wrongly pick oxygen because we breathe it - nitrogen dominates by volume.

  3. Question 3

    Q3. The hardest natural substance on Earth is:

    • A) Gold
    • B) Iron
    • C) Diamond
    • D) Platinum

    Answer: Diamond

    Explanation: Diamond ranks 10 on Mohs hardness scale. Used in cutting tools. Gold/platinum are precious metals, not hardest minerals.

  4. Question 4

    Q4. Largest proportion of Earth's atmosphere by volume?

    • A) Oxygen
    • B) Carbon dioxide
    • C) Nitrogen
    • D) Argon

    Answer: Nitrogen

    Explanation: Nitrogen ~78%, oxygen ~21%. CO₂ is a trace gas. This fact often appears in ISSB academic and general knowledge sections.

  5. Question 5

    Q5. Chemical symbol for Gold?

    • A) Go
    • B) Gd
    • C) Au
    • D) Ag

    Answer: Au

    Explanation: Au from Latin 'aurum.' Ag is silver. This fact often appears in ISSB academic and general knowledge sections.

  6. Question 6

    Q6. SI unit of electric current?

    • A) Volt
    • B) Ohm
    • C) Ampere
    • D) Watt

    Answer: Ampere

    Explanation: Ampere (A). Volt = potential; ohm = resistance; watt = power. This fact often appears in ISSB academic and general knowledge sections.

  7. Question 7

    Q7. Which planet has the most moons (current records)?

    • A) Jupiter
    • B) Saturn
    • C) Uranus
    • D) Neptune

    Answer: Saturn

    Explanation: Recent discoveries pushed Saturn above Jupiter - common GK trap. This fact often appears in ISSB academic and general knowledge sections.

  8. Question 8

    Q8. Which gas do plants absorb during photosynthesis?

    • A) Oxygen
    • B) Nitrogen
    • C) Carbon dioxide
    • D) Hydrogen

    Answer: Carbon dioxide

    Explanation: Plants use CO₂ and release O₂ during photosynthesis. This fact often appears in ISSB academic and general knowledge sections.

  9. Question 9

    Q9. Which organ in human body filters blood?

    • A) Heart
    • B) Liver
    • C) Kidney
    • D) Lungs

    Answer: Kidney

    Explanation: Kidneys filter waste and excess fluid. Liver detoxifies but primary filter is kidney.

  10. Question 10

    Q10. Deficiency of Vitamin D causes:

    • A) Scurvy
    • B) Rickets
    • C) Beriberi
    • D) Pellagra

    Answer: Rickets

    Explanation: Vitamin D deficiency leads to rickets (bone softening). Scurvy = Vitamin C.

  11. Question 11

    Q11. Instrument to measure earthquake intensity?

    • A) Barometer
    • B) Seismograph
    • C) Thermometer
    • D) Anemometer

    Answer: Seismograph

    Explanation: Seismograph records seismic waves. Barometer measures air pressure. This fact often appears in ISSB academic and general knowledge sections.

  12. Question 12

    Q12. Speed of light in vacuum (approx)?

    • A) 3×10⁶ m/s
    • B) 3×10⁸ m/s
    • C) 3×10¹⁰ m/s
    • D) 3×10⁵ m/s

    Answer: 3×10⁸ m/s

    Explanation: ≈ 299,792,458 m/s, often rounded to 3×10⁸ m/s in MCQs. Work each step carefully; ISSB math rewards accuracy under time pressure.

  13. Question 13

    Q13. Human body largest organ by surface area?

    • A) Liver
    • B) Skin
    • C) Lungs
    • D) Brain

    Answer: Skin

    Explanation: Skin covers the entire body. Liver is the largest internal organ but not by surface area.

  14. Question 14

    Q14. Normal human body temperature in Celsius?

    • A) 35 C
    • B) 36.5 C
    • C) 37 C
    • D) 38 C

    Answer: 37 C

    Explanation: About 37 C or 98.6 F. Slight variation is normal. 38 C usually indicates fever.

  15. Question 15

    Q15. Which gas is most abundant in the Sun?

    • A) Oxygen
    • B) Hydrogen
    • C) Helium
    • D) Nitrogen

    Answer: Hydrogen

    Explanation: The Sun is mostly hydrogen fusing into helium. Helium is second, not first.

  16. Question 16

    Q16. First man to walk on the Moon?

    • A) Yuri Gagarin
    • B) Neil Armstrong
    • C) Buzz Aldrin
    • D) John Glenn

    Answer: Neil Armstrong

    Explanation: Armstrong stepped on the Moon in 1969. Gagarin was first in space. Aldrin followed Armstrong on the same mission.

  17. Question 17

    Q17. Vitamin C deficiency causes:

    • A) Rickets
    • B) Scurvy
    • C) Beriberi
    • D) Night blindness

    Answer: Scurvy

    Explanation: Scurvy comes from lack of vitamin C. Rickets is vitamin D. Night blindness links to vitamin A.

  18. Question 18

    Q18. Hardest natural substance?

    • A) Gold
    • B) Iron
    • C) Diamond
    • D) Granite

    Answer: Diamond

    Explanation: Diamond ranks 10 on Mohs hardness scale. Granite is hard rock but not the hardest material.

  19. Question 19

    Q19. Blood group known as universal donor (RBC transfusion context)?

    • A) A
    • B) B
    • C) AB
    • D) O negative

    Answer: O negative

    Explanation: O negative red cells lack A and B antigens, so they are used in emergencies. AB positive is often called universal recipient.

  20. Question 20

    Q20. Largest mammal?

    • A) African elephant
    • B) Blue whale
    • C) Giraffe
    • D) Polar bear

    Answer: Blue whale

    Explanation: Blue whale outweighs any land animal. Elephant is largest land mammal. This fact often appears in ISSB academic and general knowledge sections.

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