GK — Science & Technology

1. What is the SI unit of pressure?

• A. Newton
• B. Pascal (Correct)
• C. Bar
• D. Joule

Explanation: The pascal (Pa) is the SI unit of pressure, defined as one newton per square metre (N/m²).

2. Which gas is used in fire extinguishers?

• A. Oxygen
• B. Nitrogen
• C. Carbon dioxide (Correct)
• D. Hydrogen

Explanation: CO₂ is used in fire extinguishers because it displaces oxygen, smothering the fire without damaging equipment.

3. The largest organ of the human body is:

• A. Liver
• B. Heart
• C. Skin (Correct)
• D. Lungs

Explanation: The skin is the largest organ of the human body by surface area and weight, covering approximately 2 m².

4. Which law states: 'For every action, there is an equal and opposite reaction'?

• A. Newton's First Law
• B. Newton's Second Law
• C. Newton's Third Law (Correct)
• D. Law of Gravitation

Explanation: Newton's Third Law of Motion: every action force has an equal (in magnitude) and opposite (in direction) reaction force.

5. The atomic number of Carbon is:

• A. 4
• B. 6 (Correct)
• C. 8
• D. 12

Explanation: Carbon (C) has atomic number 6, meaning it has 6 protons in its nucleus.

6. Blood group O is called the 'universal donor' because:

• A. It has both A and B antigens
• B. It has no A or B antigens (Correct)
• C. It has Rh factor
• D. It has AB antigens

Explanation: Blood group O has no A or B antigens on red blood cells, so it won't cause agglutination reactions in any recipient.

7. RAM stands for:

• A. Read Access Memory
• B. Random Access Memory (Correct)
• C. Read Anywhere Memory
• D. Rapid Access Memory

Explanation: RAM (Random Access Memory) is a type of computer memory that can be accessed randomly and quickly — it stores data currently in use.

8. The speed of sound in air at 20°C is approximately:

• A. 300 m/s
• B. 343 m/s (Correct)
• C. 400 m/s
• D. 500 m/s

Explanation: The speed of sound in air at room temperature (20°C) is approximately 343 m/s or 1,234 km/h.

9. The process of conversion of solid directly to gas (without liquid stage) is:

• A. Evaporation
• B. Condensation
• C. Sublimation (Correct)
• D. Deposition

Explanation: Sublimation is the direct phase transition from solid to gas. Examples: dry ice (CO₂), iodine, camphor, and naphthalene.

10. Which organelle is responsible for protein synthesis?

• A. Nucleus
• B. Mitochondria
• C. Ribosome (Correct)
• D. Lysosome

Explanation: Ribosomes are the molecular machines responsible for protein synthesis (translation), reading mRNA to assemble amino acids.

11. Which type of mirror is used in a car's rear-view mirror?

• A. Plane
• B. Concave
• C. Convex (Correct)
• D. Parabolic

Explanation: Convex mirrors are used as rear-view mirrors because they provide a wider field of view (diverging reflected rays).

12. Which protocol is used to send emails?

• A. HTTP
• B. FTP
• C. SMTP (Correct)
• D. TCP

Explanation: SMTP (Simple Mail Transfer Protocol) is used for sending emails from a client to a server or between mail servers.

13. Rusting of iron is a process of:

• A. Reduction
• B. Oxidation (Correct)
• C. Neutralization
• D. Distillation

Explanation: Rusting (corrosion of iron) is an oxidation reaction: 4Fe + 3O₂ + 6H₂O → 4Fe(OH)₃ → 2Fe₂O₃·3H₂O.

14. The study of insects is called:

• A. Entomology (Correct)
• B. Ornithology
• C. Ichthyology
• D. Herpetology

Explanation: Entomology is the scientific study of insects. Ornithology = birds, Ichthyology = fish, Herpetology = reptiles & amphibians.

15. Which phenomenon explains the blue colour of the sky?

• A. Reflection
• B. Refraction
• C. Dispersion
• D. Scattering (Correct)

Explanation: The sky appears blue due to Rayleigh scattering — shorter wavelength blue light scatters more than longer wavelengths when sunlight passes through the atmosphere.

16. The full form of GPS is:

• A. Global Positioning System (Correct)
• B. General Positioning Satellite
• C. Global Position Satellite
• D. Geographic Position System

Explanation: GPS (Global Positioning System) is a satellite-based navigation system that provides location and time information anywhere on Earth.

17. What is the pH of a neutral solution?

• A. 0
• B. 7 (Correct)
• C. 10
• D. 14

Explanation: A neutral solution has pH = 7. Below 7 is acidic; above 7 is basic/alkaline.

18. Insulin is secreted by which gland?

• A. Thyroid
• B. Pituitary
• C. Pancreas (Correct)
• D. Adrenal

Explanation: Insulin is produced by beta cells in the islets of Langerhans in the pancreas. It regulates blood glucose levels.

19. The instrument used to measure atmospheric pressure is:

• A. Thermometer
• B. Barometer (Correct)
• C. Hygrometer
• D. Anemometer

Explanation: A barometer measures atmospheric (air) pressure. Torricelli invented the mercury barometer in 1643.

20. Which company developed the Android operating system?

• A. Apple
• B. Microsoft
• C. Google (Correct)
• D. Samsung

Explanation: Android was developed by Android Inc., which was acquired by Google in 2005. It was released publicly in 2008.

21. The process of splitting a heavy nucleus into two lighter nuclei is called:

• A. Fusion
• B. Fission (Correct)
• C. Radioactivity
• D. Combustion

Explanation: Nuclear fission is the splitting of a heavy atomic nucleus (e.g., U-235) into two lighter nuclei, releasing enormous energy — the principle behind nuclear reactors and atomic bombs.

22. Which blood group is considered the universal recipient?

• A. A
• B. B
• C. O
• D. AB (Correct)

Explanation: AB positive blood group is the universal recipient — people with AB+ can receive blood from all blood groups.

23. What is the unit of electric power?

• A. Volt
• B. Ampere
• C. Ohm
• D. Watt (Correct)

Explanation: The watt (W) is the SI unit of power, including electric power. 1 Watt = 1 Joule per second.

24. What does 'Blockchain' primarily ensure in digital transactions?

• A. Speed
• B. Decentralization and Immutability (Correct)
• C. Anonymity only
• D. Low cost

Explanation: Blockchain is a distributed ledger technology that ensures decentralization (no single authority) and immutability (records cannot be altered retroactively).

25. The part of the brain that controls balance and coordination is:

• A. Cerebrum
• B. Cerebellum (Correct)
• C. Medulla Oblongata
• D. Hypothalamus

Explanation: The cerebellum (at the back of the brain) controls balance, coordination of voluntary movements, and fine motor skills.