50 Essential Science GK Questions for Competitive Exams – Physics, Chemistry & Biology

Science General Knowledge is a cornerstone for success in competitive exams, encompassing principles from physics, chemistry, biology, astronomy, and environmental science. A solid grasp of fundamental concepts—like Newton’s laws, periodic table trends, cellular structure, and photoelectric effect—can make the difference in multiple-choice sections and interviews. This quiz of 50 carefully crafted questions will test your understanding of units, formulas, discoveries, scientific names, and real-world applications. Whether you’re preparing for civil services, banking, engineering entrance, or postgraduate tests, sharpening your Science GK knowledge is essential. Dive in and challenge yourself to improve accuracy and speed under exam conditions!

Science GK Quiz for Competitive Exams

1. What is the SI unit of electric current?

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

Answer: B. Ampere

2. Who proposed the theory of relativity?

• A. Isaac Newton
• B. Albert Einstein
• C. Galileo Galilei
• D. Niels Bohr

Answer: B. Albert Einstein

3. What is the chemical formula of table salt?

• A. KCl
• B. NaCl
• C. CaCl₂
• D. MgCl₂

Answer: B. NaCl

4. What gas is most abundant in Earth’s atmosphere?

• A. Oxygen
• B. Carbon Dioxide
• C. Nitrogen
• D. Argon

Answer: C. Nitrogen

5. Which vitamin is synthesized when skin is exposed to sunlight?

• A. Vitamin A
• B. Vitamin B12
• C. Vitamin C
• D. Vitamin D

Answer: D. Vitamin D

6. What is the acceleration due to gravity at Earth’s surface (approx)?

• A. 9.8 m/s²
• B. 9.8 km/s²
• C. 8.9 m/s²
• D. 10.8 m/s²

Answer: A. 9.8 m/s²

7. Which element has atomic number 6?

• A. Nitrogen
• B. Carbon
• C. Oxygen
• D. Boron

Answer: B. Carbon

8. What is the pH of pure water at 25°C?

• A. 7
• B. 14
• C. 0
• D. 1

Answer: A. 7

9. Which organelle is known as the powerhouse of the cell?

• A. Nucleus
• B. Ribosome
• C. Mitochondrion
• D. Endoplasmic Reticulum

Answer: C. Mitochondrion

10. Who is known as the father of modern chemistry?

• A. Dmitri Mendeleev
• B. Antoine Lavoisier
• C. John Dalton
• D. Robert Boyle

Answer: B. Antoine Lavoisier

11. What phenomenon explains the bending of light as it passes from air to water?

• A. Reflection
• B. Refraction
• C. Diffraction
• D. Dispersion

Answer: B. Refraction

12. Which gas is used in incandescent bulbs to prevent filament oxidation?

• A. Oxygen
• B. Nitrogen
• C. Argon
• D. Helium

Answer: C. Argon

13. What is the primary constituent of natural gas?

• A. Ethane
• B. Methane
• C. Propane
• D. Butane

Answer: B. Methane

14. Who discovered penicillin?

• A. Louis Pasteur
• B. Alexander Fleming
• C. Robert Koch
• D. Edward Jenner

Answer: B. Alexander Fleming

15. What is the chemical name for laughing gas?

• A. Nitrous oxide
• B. Nitric oxide
• C. Carbon monoxide
• D. Sulfur dioxide

Answer: A. Nitrous oxide

16. Which planet is known as the Red Planet?

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

Answer: B. Mars

17. What is the hardest natural substance on Earth?

• A. Quartz
• B. Topaz
• C. Diamond
• D. Corundum

Answer: C. Diamond

18. Which law states that pressure and volume of a gas are inversely proportional?

• A. Charles’s law
• B. Boyle’s law
• C. Avogadro’s law
• D. Gay-Lussac’s law

Answer: B. Boyle’s law

19. What phenomenon causes the sky to appear blue?

• A. Reflection
• B. Refraction
• C. Rayleigh scattering
• D. Diffraction

Answer: C. Rayleigh scattering

20. Which metal has the highest electrical conductivity?

• A. Copper
• B. Silver
• C. Gold
• D. Aluminum

Answer: B. Silver

21. What is the base unit of temperature in the SI system?

• A. Celsius
• B. Kelvin
• C. Fahrenheit
• D. Rankine

Answer: B. Kelvin

22. Which device measures atmospheric pressure?

• A. Thermometer
• B. Barometer
• C. Hygrometer
• D. Anemometer

Answer: B. Barometer

23. Who formulated the laws of motion?

• A. Albert Einstein
• B. James Clerk Maxwell
• C. Isaac Newton
• D. Michael Faraday

Answer: C. Isaac Newton

24. What is the chemical symbol for gold?

• A. Au
• B. Ag
• C. Gd
• D. Go

Answer: A. Au

25. Which vitamin is essential for blood clotting?

• A. Vitamin A
• B. Vitamin D
• C. Vitamin K
• D. Vitamin E

Answer: C. Vitamin K

26. What is the process by which plants make food?

• A. Respiration
• B. Digestion
• C. Photosynthesis
• D. Fermentation

Answer: C. Photosynthesis

27. Which particle has a positive charge?

• A. Electron
• B. Neutron
• C. Proton
• D. Photon

Answer: C. Proton

28. Which law explains the relationship between voltage, current, and resistance?

• A. Ohm’s law
• B. Faraday’s law
• C. Lenz’s law
• D. Ampère’s law

Answer: A. Ohm’s law

29. What is the study of relationships between organisms and environment?

• A. Zoology
• B. Botany
• C. Ecology
• D. Microbiology

Answer: C. Ecology

30. Which element is a halogen?

• A. Neon
• B. Chlorine
• C. Argon
• D. Xenon

Answer: B. Chlorine

31. What is the speed of light in vacuum?

• A. 3×10⁸ m/s
• B. 3×10⁶ m/s
• C. 3×10⁵ m/s
• D. 3×10⁷ m/s

Answer: A. 3×10⁸ m/s

32. Which organ system controls hormones?

• A. Nervous
• B. Digestive
• C. Endocrine
• D. Circulatory

Answer: C. Endocrine

33. What is the powerhouse of a nuclear reactor?

• A. Uranium fuel rods
• B. Control rods
• C. Moderator
• D. Coolant

Answer: A. Uranium fuel rods

34. Which biomolecule is the main component of cell membranes?

• A. Carbohydrates
• B. Proteins
• C. Lipids
• D. Nucleic acids

Answer: C. Lipids

35. What phenomenon describes emission of electrons when light shines on metal?

• A. Photoelectric effect
• B. Compton effect
• C. Raman scattering
• D. Tyndall effect

Answer: A. Photoelectric effect

36. Which process converts solid directly to gas?

• A. Condensation
• B. Sublimation
• C. Evaporation
• D. Deposition

Answer: B. Sublimation

37. What is the study of celestial objects called?

• A. Meteorology
• B. Geology
• C. Astronomy
• D. Astrology

Answer: C. Astronomy

38. Which law explains ideal gas at constant temperature?

• A. Boyle’s law
• B. Charles’s law
• C. Gay-Lussac’s law
• D. Avogadro’s law

Answer: A. Boyle’s law

39. What is the common name for dihydrogen monoxide?

• A. Hydrogen peroxide
• B. Water
• C. Hydrochloric acid
• D. Methane

Answer: B. Water

40. Which element is liquid at room temperature?

• A. Mercury
• B. Bromine
• C. Both A and B
• D. Gallium

Answer: C. Both A and B

41. Which mineral is the main component of limestone?

• A. Quartz
• B. Feldspar
• C. Calcite
• D. Gypsum

Answer: C. Calcite

42. What is the genetic material in most living organisms?

• A. RNA
• B. DNA
• C. Protein
• D. Lipid

Answer: B. DNA

43. Which phenomenon keeps planets in orbit around the sun?

• A. Electromagnetism
• B. Inertia
• C. Gravity
• D. Friction

Answer: C. Gravity

44. What is the process of cell division in somatic cells?

• A. Meiosis
• B. Mitosis
• C. Binary fission
• D. Budding

Answer: B. Mitosis

45. Which device converts chemical energy into electrical energy?

• A. Generator
• B. Motor
• C. Battery
• D. Transformer

Answer: C. Battery

46. What is the boiling point of water at sea level?

• A. 90°C
• B. 100°C
• C. 212°C
• D. 373 K

Answer: B. 100°C

47. Which element is used as the standard for atomic mass?

• A. Carbon-12
• B. Oxygen-16
• C. Hydrogen-1
• D. Nitrogen-14

Answer: A. Carbon-12

48. Which layer of the Earth is liquid?

• A. Crust
• B. Outer core
• C. Inner core
• D. Mantle

Answer: B. Outer core

49. What is the chemical symbol for potassium?

• A. P
• B. Pt
• C. K
• D. Po

Answer: C. K

50. Which phenomenon keeps an aircraft aloft?

• A. Thrust
• B. Drag
• C. Lift
• D. Weight

Answer: C. Lift