UPSC Science MCQs – 25 Important Questions for Prelims Practice

Science and Technology form an important part of the UPSC Civil Services Examination, particularly in the Prelims stage. Questions from science are generally based on basic concepts from Physics, Chemistry, and Biology, along with their practical applications in daily life.

Unlike other subjects, UPSC science questions usually focus on conceptual understanding rather than complex formulas or advanced theories.

UPSC: Science MCQs - 25 Questions

For UPSC aspirants, practicing Science Multiple Choice Questions (MCQs) is a useful strategy to strengthen fundamental concepts and improve problem-solving skills. Regular practice also helps candidates identify commonly asked topics and develop the ability to eliminate incorrect options during the exam.

The following set of 25 Science MCQs covers important concepts from basic science that are frequently asked in the UPSC examination.

UPSC Science MCQ Practice Set - 25 Questions

Physics

1. The unit of force in the International System (SI) is:

A. Joule
B. Newton
C. Watt
D. Pascal

2. Which form of energy is stored in a stretched spring?

A. Kinetic energy
B. Potential energy
C. Thermal energy
D. Chemical energy

3. Sound travels fastest in:

A. Air
B. Water
C. Vacuum
D. Solids

4. Which device is used to measure electric current?

A. Voltmeter
B. Ammeter
C. Barometer
D. Thermometer

5. The phenomenon responsible for the blue color of the sky is:

A. Reflection
B. Refraction
C. Scattering of light
D. Diffraction

Chemistry

6. The most abundant gas in the Earth's atmosphere is:

A. Oxygen
B. Carbon dioxide
C. Nitrogen
D. Hydrogen

7. The pH value of a neutral solution is:

A. 0
B. 7
C. 14
D. 10

8. Rusting of iron is an example of:

A. Reduction
B. Oxidation
C. Neutralization
D. Precipitation

9. Which element is essential for the formation of hemoglobin in blood?

A. Calcium
B. Iron
C. Sodium
D. Potassium

10. Which gas is commonly known as laughing gas?

A. Nitrous oxide
B. Carbon monoxide
C. Methane
D. Hydrogen

Biology

11. The basic structural and functional unit of life is:

A. Tissue
B. Organ
C. Cell
D. Molecule

12. Photosynthesis occurs mainly in which part of the plant cell?

A. Mitochondria
B. Chloroplast
C. Nucleus
D. Ribosome

13. Which vitamin is produced in the human body when exposed to sunlight?

A. Vitamin A
B. Vitamin B
C. Vitamin C
D. Vitamin D

14. The human heart has how many chambers?

A. Two
B. Three
C. Four
D. Five

15. Which blood cells help in fighting infections?

A. Red blood cells
B. White blood cells
C. Platelets
D. Plasma

Environmental Science

16. Which gas is mainly responsible for global warming?

A. Oxygen
B. Carbon dioxide
C. Nitrogen
D. Helium

17. The ozone layer protects the Earth from:

A. Visible light
B. Infrared radiation
C. Ultraviolet radiation
D. Radio waves

18. Which of the following is a renewable source of energy?

A. Coal
B. Petroleum
C. Solar energy
D. Natural gas

19. Acid rain is mainly caused by:

A. Carbon dioxide
B. Sulfur dioxide
C. Oxygen
D. Hydrogen

20. The main cause of ozone layer depletion is:

A. Carbon dioxide
B. Chlorofluorocarbons (CFCs)
C. Methane
D. Nitrogen

Miscellaneous Science

21. The human brain is part of which system of the body?

A. Circulatory system
B. Digestive system
C. Nervous system
D. Respiratory system

22. Which planet is known as the Red Planet?

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

23. Water boils at what temperature at sea level?

A. 90°C
B. 100°C
C. 120°C
D. 80°C

24. The process of converting liquid into vapor is called:

A. Condensation
B. Evaporation
C. Precipitation
D. Sublimation

25. The SI unit of temperature is:

A. Celsius
B. Kelvin
C. Fahrenheit
D. Joule

Answer Key

Conclusion

Science MCQ practice is essential for UPSC aspirants because it strengthens fundamental knowledge and improves analytical thinking. Since UPSC questions from science are usually conceptual, understanding basic principles in physics, chemistry, and biology is more important than memorizing facts.

By consistently practicing MCQs and revising key scientific concepts, candidates can significantly improve their performance in the UPSC Civil Services Preliminary Examination.