30 General Science MCQs for RRB Group D With Answers
Preparing for RRB Group D? General Science is one of the easiest and most scoring sections. Here are 30 high-quality MCQs from Physics, Chemistry, and Biology, each with the correct answer and a clear explanation to help you understand the concept better and boost your exam preparation.
1. Which gas is essential for photosynthesis?
A. Nitrogen
B. Carbon dioxide
C. Oxygen
D. Hydrogen
Answer: B. Carbon dioxide
Explanation: Plants absorb carbon dioxide from the air and convert it into glucose during photosynthesis using sunlight. It is the main raw material along with water. Without CO₂, plants cannot make food or release oxygen. This process supports life on Earth by maintaining oxygen levels.
2. Which vitamin is produced in the body with the help of sunlight?
A. Vitamin A
B. Vitamin B12
C. Vitamin C
D. Vitamin D
Answer: D. Vitamin D
Explanation: Sunlight helps the skin synthesize Vitamin D, which is important for calcium absorption and bone health. People who get little sunlight are more likely to suffer from Vitamin D deficiency. It supports immunity, mood regulation, and overall well-being.
3. What is the SI unit of force?
A. Pascal
B. Newton
C. Joule
D. Watt
Answer: B. Newton
Explanation: Force is measured in Newtons, named after physicist Sir Isaac Newton. One Newton represents the force needed to accelerate one kilogram of mass at one meter per second squared. It helps quantify pushing and pulling actions in physics.
4. Which part of the cell contains genetic material?
A. Mitochondria
B. Nucleus
C. Ribosome
D. Golgi body
Answer: B. Nucleus
Explanation: The nucleus stores DNA, which carries hereditary information passed from one generation to another. It controls cell growth, division, and functioning. Without the nucleus, cells cannot regulate their activities or reproduce properly.
5. Which metal is liquid at room temperature?
A. Mercury
B. Iron
C. Aluminium
D. Sodium
Answer: A. Mercury
Explanation: Mercury is the only metal that remains liquid at room temperature due to its low melting point. It is used in thermometers, electrical switches, and scientific equipment. Its unique fluid state makes it useful for temperature measurement.
6. Which organ purifies blood in the human body?
A. Heart
B. Stomach
C. Kidney
D. Lungs
Answer: C. Kidney
Explanation: Kidneys filter waste products and excess water from the blood to form urine. They help maintain fluid balance, regulate minerals, and remove toxins. Without healthy kidneys, harmful substances can build up in the body.
7. Which gas is commonly known as laughing gas?
A. Carbon monoxide
B. Nitrous oxide
C. Sulphur dioxide
D. Methane
Answer: B. Nitrous oxide
Explanation: Nitrous oxide is known as laughing gas because inhaling it can cause temporary euphoria and laughter. It is widely used as a mild anesthetic in dental and medical procedures. The gas contains nitrogen and oxygen.
8. What is the basic unit of life?
A. Tissue
B. Cell
C. Organ
D. Organ system
Answer: B. Cell
Explanation: A cell is the smallest unit capable of performing life functions like respiration, growth, and reproduction. All organisms are made of one or more cells. Cells group together to form tissues and organs in higher organisms.
9. Which planet is known as the Red Planet?
A. Venus
B. Jupiter
C. Mars
D. Saturn
Answer: C. Mars
Explanation: Mars appears red due to the presence of iron oxide (rust) on its surface. The reddish color is visible even from telescopes. It is a cold, desert-like planet and is frequently studied for signs of past life.
10. What is the chemical formula of water?
A. CO₂
B. H₂O
C. O₂
D. NaCl
Answer: B. H₂O
Explanation: Water consists of two hydrogen atoms linked to one oxygen atom. This simple molecule is essential for all known forms of life. Water’s unique chemical properties help regulate temperature and support biological processes.
11. Which blood cells help in clotting?
A. RBC
B. WBC
C. Platelets
D. Plasma
Answer: C. Platelets
Explanation: Platelets are small, disc-shaped cells that help stop bleeding by forming clots at wound sites. They gather at the injury location and form a plug. Without platelets, even small cuts would lead to excessive bleeding.
12. Sound travels fastest in which medium?
A. Air
B. Water
C. Vacuum
D. Steel
Answer: D. Steel
Explanation: Sound travels fastest in solids because particles are tightly packed. Steel, being a dense solid, allows sound waves to move quickly through it. In contrast, sound travels slower in air and cannot travel at all in a vacuum.
13. Which gas do plants release during photosynthesis?
A. Nitrogen
B. Carbon dioxide
C. Oxygen
D. Hydrogen
Answer: C. Oxygen
Explanation: Plants release oxygen during photosynthesis as a by-product. They absorb carbon dioxide and convert it into glucose. This oxygen supports life by allowing animals and humans to breathe.
14. Which disease is caused by the deficiency of iodine?
A. Scurvy
B. Goiter
C. Rickets
D. Anemia
Answer: B. Goiter
Explanation: Goiter results from iodine deficiency, causing the thyroid gland to swell. Iodine helps produce thyroid hormones that regulate metabolism. Using iodized salt is the easiest way to prevent goiter.
15. Which instrument is used to measure temperature?
A. Barometer
B. Thermometer
C. Hygrometer
D. Anemometer
Answer: B. Thermometer
Explanation: Thermometers measure temperature using mercury, alcohol, or electronic sensors. They display values in Celsius, Fahrenheit, or Kelvin. They are essential in weather forecasting, medical use, and laboratory work.
16. The ozone layer is found in which part of the atmosphere?
A. Troposphere
B. Stratosphere
C. Mesosphere
D. Thermosphere
Answer: B. Stratosphere
Explanation: The ozone layer lies in the stratosphere and protects Earth by absorbing harmful ultraviolet rays from the sun. Without it, life on Earth would be exposed to dangerous radiation.
17. Which organ is known as the powerhouse of the cell?
A. Ribosome
B. Mitochondria
C. Golgi apparatus
D. Vacuole
Answer: B. Mitochondria
Explanation: Mitochondria generate ATP, the energy currency of the cell. They provide power for all cellular activities. Cells that require more energy, like muscle cells, contain a higher number of mitochondria.
18. What is the pH value of pure water?
A. 5
B. 7
C. 9
D. 11
Answer: B. 7
Explanation: Pure water has a neutral pH of 7 on the pH scale. This means it is neither acidic nor alkaline. pH measures how acidic or basic a substance is, ranging from 0 to 14.
19. Which vitamin helps in blood clotting?
A. Vitamin E
B. Vitamin K
C. Vitamin B
D. Vitamin D
Answer: B. Vitamin K
Explanation: Vitamin K is essential for producing blood-clotting proteins. It prevents excessive bleeding and helps wounds heal properly. A deficiency can lead to slow clotting.
20. Which gas is used in balloons?
A. Oxygen
B. Nitrogen
C. Helium
D. Argon
Answer: C. Helium
Explanation: Helium is lighter than air and non-flammable, making it ideal for balloons. Its low density allows balloons to float safely without the risk of explosion like hydrogen.
21. What is the nearest star to Earth?
A. Proxima Centauri
B. Vega
C. Sun
D. Sirius
Answer: C. Sun
Explanation: The Sun is the closest star to Earth and provides the heat and light necessary for sustaining life. It influences weather, climate, and natural processes on our planet.
22. Which hormone controls blood sugar levels?
A. Adrenaline
B. Thyroxine
C. Insulin
D. Estrogen
Answer: C. Insulin
Explanation: Insulin, produced by the pancreas, helps regulate blood sugar by allowing cells to absorb glucose. A lack of insulin leads to diabetes, making it crucial for maintaining energy levels.
23. Which liquid is used in car batteries?
A. Distilled water
B. Hydrochloric acid
C. Sulphuric acid
D. Acetic acid
Answer: C. Sulphuric acid
Explanation: Car batteries contain diluted sulphuric acid as the electrolyte. It helps produce electric current by enabling chemical reactions inside the battery. Without it, the battery cannot function.
24. What is the main component of natural gas?
A. Propane
B. Methane
C. Ethane
D. Butane
Answer: B. Methane
Explanation: Methane is the primary component of natural gas. It burns cleanly and is widely used for cooking and heating. Its low carbon emissions make it an environment-friendly fuel.
25. Which part of the plant absorbs water?
A. Stem
B. Leaf
C. Fruit
D. Root
Answer: D. Root
Explanation: Roots absorb water and minerals from the soil using tiny root hairs. They anchor the plant and help transport water upward through the stem to the leaves.
26. Which phenomenon causes the rainbow?
A. Reflection
B. Refraction
C. Diffraction
D. Interference
Answer: B. Refraction
Explanation: Rainbows form when sunlight bends (refracts), reflects, and disperses inside water droplets, separating light into seven colors. This natural phenomenon appears after rain when sunlight hits moisture in the air.
27. Which disease is caused by a virus?
A. Cholera
B. Tuberculosis
C. Polio
D. Typhoid
Answer: C. Polio
Explanation: Polio is caused by the poliovirus and affects the nervous system, sometimes causing paralysis. Large-scale vaccination programs have significantly reduced polio cases worldwide.
28. What is the hardest natural substance?
A. Gold
B. Diamond
C. Iron
D. Quartz
Answer: B. Diamond
Explanation: Diamond is the hardest naturally occurring substance due to its strong carbon structure. It is used in cutting tools, drilling equipment, and jewelry.
29. Which element is necessary for the formation of haemoglobin?
A. Calcium
B. Iron
C. Sodium
D. Potassium
Answer: B. Iron
Explanation: Iron is essential for producing haemoglobin, the protein in red blood cells that carries oxygen. Iron deficiency leads to anemia, causing fatigue and weakness.
30. Which gas do humans exhale during respiration?
A. Oxygen
B. Hydrogen
C. Nitrogen
D. Carbon dioxide
Answer: D. Carbon dioxide
Explanation: Humans inhale oxygen and exhale carbon dioxide after the body uses oxygen for energy production. This gas is expelled through the lungs as a waste product.
Conclusion
These 30 General Science MCQs are perfect for RRB Group D aspirants. They help you revise core topics quickly and improve your confidence for the exam. Regular practice of such questions boosts speed, accuracy, and overall performance.