RRB NTPC 2025 Science MCQ Series , Answers And Explaination

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  1. What is the SI unit of electric current?
  2. Volt
    B. Ampere
    C. Coulomb
    D. Ohm
    Answer: B. Ampere
    Explanation: The ampere (A) is the base unit of electric current in the International System of Units (SI).
  3. Which gas is most abundant in Earth’s atmosphere?
  4. Oxygen
    B. Carbon dioxide
    C. Nitrogen
    D. Hydrogen
    Answer: C. Nitrogen
    Explanation: Nitrogen constitutes about 78% of the Earth’s atmosphere, making it the most abundant gas.
  5. Which vitamin is responsible for blood clotting?
  6. Vitamin A
    B. Vitamin C
    C. Vitamin K
    D. Vitamin D
    Answer: C. Vitamin K
    Explanation: Vitamin K is essential for synthesizing proteins required for blood coagulation.
  7. What is the chemical formula of baking soda?
  8. NaCl
    B. NaHCO₃
    C. KCl
    D. CaCO₃
    Answer: B. NaHCO₃
    Explanation: Baking soda is sodium bicarbonate, with the chemical formula NaHCO₃.
  9. The hardest natural substance on Earth is:
  10. Graphite
    B. Diamond
    C. Quartz
    D. Topaz
    Answer: B. Diamond
    Explanation: Diamond, a form of carbon, is the hardest naturally occurring material.
  11. What is the function of xylem in plants?
  12. Transport of food
    B. Transport of water
    C. Photosynthesis
    D. Reproduction
    Answer: B. Transport of water
    Explanation: Xylem is a vascular tissue responsible for transporting water and nutrients from roots to other parts of the plant.
  13. The phenomenon of splitting of white light into its constituent colors is called:
  14. Refraction
    B. Dispersion
    C. Reflection
    D. Diffraction
    Answer: B. Dispersion
    Explanation: Dispersion occurs when light passes through a prism, splitting into its spectrum of colors.
  15. Which planet is known as the “Red Planet”?
  16. Venus
    B. Mars
    C. Jupiter
    D. Mercury
    Answer: B. Mars
    Explanation: Mars is called the Red Planet due to its reddish appearance, caused by iron oxide (rust) on its surface.
  17. What is the boiling point of water at sea level?
  18. 50°C
    B. 100°C
    C. 150°C
    D. 200°C
    Answer: B. 100°C
    Explanation: At sea level, water boils at 100°C under standard atmospheric pressure.
  19. Which part of the cell is responsible for energy production?
  20. Nucleus
    B. Mitochondria
    C. Ribosomes
    D. Lysosomes
    Answer: B. Mitochondria
    Explanation: Mitochondria are known as the “powerhouses” of the cell, producing energy in the form of ATP.
  21. The primary source of energy for Earth is:
  22. Wind
    B. Fossil fuels
    C. The Sun
    D. Geothermal energy
    Answer: C. The Sun
    Explanation: The Sun provides energy for most natural processes on Earth, including photosynthesis and the water cycle.
  23. Which element is a liquid at room temperature?
  24. Mercury
    B. Gold
    C. Sodium
    D. Copper
    Answer: A. Mercury
    Explanation: Mercury is the only metal that is liquid at room temperature.
  25. Which organ in the human body filters blood?
  26. Heart
    B. Kidney
    C. Liver
    D. Lungs
    Answer: B. Kidney
    Explanation: Kidneys filter waste products from the blood to form urine.
  27. The pH of pure water is:
  28. 7
    B. 0
    C. 14
    D. 1
    Answer: A. 7
    Explanation: Pure water is neutral, with a pH of 7.
  29. What is the smallest particle of an element?
  30. Molecule
    B. Atom
    C. Proton
    D. Neutron
    Answer: B. Atom
    Explanation: Atoms are the basic building blocks of matter and the smallest unit of an element.
  31. What type of lens is used to correct myopia?
  32. Convex lens
    B. Concave lens
    C. Cylindrical lens
    D. Plane lens
    Answer: B. Concave lens
    Explanation: Myopia (nearsightedness) is corrected using concave lenses, which diverge light rays.
  33. The process by which plants make food is called:
  34. Respiration
    B. Photosynthesis
    C. Transpiration
    D. Fermentation
    Answer: B. Photosynthesis
    Explanation: Photosynthesis is the process where plants use sunlight, carbon dioxide, and water to produce glucose and oxygen.
  35. What is the most common element in the human body?
  36. Carbon
    B. Oxygen
    C. Hydrogen
    D. Nitrogen
    Answer: B. Oxygen
    Explanation: Oxygen makes up about 65% of the human body by mass, primarily in water and biological molecules.
  37. The speed of light in a vacuum is approximately:
  38. 3 × 10⁶ m/s
    B. 3 × 10⁷ m/s
    C. 3 × 10⁸ m/s
    D. 3 × 10⁹ m/s
    Answer: C. 3 × 10⁸ m/s
    Explanation: Light travels at a speed of approximately 300,000 km/s (or 3 × 10⁸ m/s) in a vacuum.
  39. Which of the following is a renewable energy source?
  40. Coal
    B. Oil
    C. Solar energy
    D. Natural gas
    Answer: C. Solar energy
    Explanation: Solar energy is a renewable energy source as it is derived from the Sun and is inexhaustible.

 

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