The General Science section is a major scoring component in Railway Recruitment Board (RRB) exams like NTPC, Group D, and ALP, comprising questions from Physics, Chemistry, and Biology. Based primarily on Class 10 NCERT standards, this section evaluates fundamental scientific laws, chemical reactions, human physiology, and everyday applications. Mastering these core principles ensures aspirants can secure high marks and clear competitive cutoff thresholds.
1. What is the SI unit of force?
Correct Answer: b) Newton
Explanation:
The standard International System of Units (SI) unit for force is the Newton, which is defined as the force needed to accelerate one kilogram of mass at the rate of one meter per second squared.
2. A light year is a unit of measurement for what?
Correct Answer: c) Distance
Explanation:
A light year is a unit of distance. It represents the distance that light travels in a vacuum in one Julian year (about 9.46 trillion kilometers).
3. Which instrument is used to measure electric current?
Correct Answer: c) Ammeter
Explanation:
An ammeter is a measuring instrument used to measure the electric current in a circuit. It is always connected in series.
4. The rate of change of momentum of a body is directly proportional to the applied:
Correct Answer: d) Force
Explanation:
According to Newton's Second Law of Motion, the rate of change of momentum of an object is directly proportional to the unbalanced external force applied to it.
5. What is the approximate value of acceleration due to gravity (g) on the surface of the Earth?
Correct Answer: a) 9.8 m/s^2
Explanation:
The standard acceleration due to gravity at the Earth's surface is approximately 9.8 meters per second squared.
6. What is the escape velocity from the Earth's surface?
Correct Answer: b) 11.2 km/s
Explanation:
The escape velocity from Earth is about 11.2 kilometers per second, which is the speed needed to break free from the Earth's gravitational pull.
7. Which type of lens is used to correct myopia (short-sightedness)?
Correct Answer: c) Concave lens
Explanation:
Myopia or short-sightedness is corrected using a concave (diverging) lens, which helps to focus the image exactly on the retina.
8. Sound waves in the air are purely:
Correct Answer: c) Longitudinal
Explanation:
Sound waves traveling through air are longitudinal waves, meaning the particle displacement is parallel to the direction of wave propagation.
9. Which of the following are the primary colors of light?
Correct Answer: b) Red, Green, Blue
Explanation:
The primary colors of light are red, green, and blue (RGB). Combining these colored lights in various ways can produce all other colors.
10. The filament of an electric bulb is made of:
Correct Answer: c) Tungsten
Explanation:
Tungsten is used for making bulb filaments because it has a very high melting point and retains its strength at extremely high temperatures.
11. What is the formula for calculating kinetic energy?
Correct Answer: c) 1/2 mv^2
Explanation:
Kinetic energy is calculated as half the mass times the velocity squared (KE = 1/2 mv^2).
12. The inertia of an object tends to cause the object to:
Correct Answer: c) Resist any change in its state of motion
Explanation:
Inertia is the inherent property of matter that causes it to resist any change in its velocity (speed or direction).
13. Which device converts mechanical energy into electrical energy?
Correct Answer: b) Electric generator
Explanation:
An electric generator uses electromagnetic induction to convert mechanical energy (like rotation) into electrical energy.
14. In which medium is the speed of sound the maximum?
Correct Answer: d) Solids
Explanation:
Sound travels fastest in solids because the molecules in a solid are tightly packed together, allowing the sound waves to transfer energy more rapidly.
15. The twinkling of stars is primarily due to:
Correct Answer: c) Atmospheric refraction of starlight
Explanation:
As starlight passes through the Earth's atmosphere, it bends (refracts) continuously due to changing air densities, causing the twinkling effect.
16. Which type of mirror is used as a rear-view mirror in vehicles?
Correct Answer: c) Convex mirror
Explanation:
Convex mirrors are used in vehicles because they always produce an erect, diminished image, providing a wider field of view of the traffic behind.
17. What is the SI unit of power?
Correct Answer: b) Watt
Explanation:
The SI unit of power is the Watt, which is equivalent to one Joule per second.
18. Who discovered radioactivity?
Correct Answer: c) Henri Becquerel
Explanation:
Radioactivity was discovered by Henri Becquerel in 1896 when he observed that uranium salts emitted rays that could expose photographic plates.
19. Who discovered X-rays?
Correct Answer: a) Wilhelm Roentgen
Explanation:
X-rays were discovered by German physicist Wilhelm Conrad Roentgen in 1895.
20. What is the SI unit of pressure?
Correct Answer: b) Pascal
Explanation:
The SI unit of pressure is the Pascal (Pa), which is equal to one Newton per square meter.
21. The splitting of white light into its component colors is called:
Correct Answer: c) Dispersion
Explanation:
Dispersion is the phenomenon where white light separates into a spectrum of colors when passing through a prism due to different wavelengths refracting at different angles.
22. Why does the sky appear blue?
Correct Answer: b) Scattering of light
Explanation:
The sky appears blue because molecules in the air scatter blue light from the sun more than they scatter red light, due to its shorter wavelength (Rayleigh scattering).
23. Optical fibers work on the principle of:
Correct Answer: a) Total internal reflection
Explanation:
Optical fibers transmit light signals over long distances by trapping the light inside the core through total internal reflection.
24. Which instrument is used to measure altitude in aircraft?
Correct Answer: b) Altimeter
Explanation:
An altimeter is a device used in aircraft to measure altitude, typically by measuring atmospheric pressure.
25. What is the SI unit of frequency?
Correct Answer: a) Hertz
Explanation:
The SI unit of frequency is the Hertz (Hz), which represents one cycle per second.
26. What is the normal temperature of the human body in Celsius?
Correct Answer: b) 37 degrees C
Explanation:
The normal average human body temperature is generally accepted as 37 degrees Celsius (or 98.6 degrees Fahrenheit).
27. Which instrument is used to measure atmospheric pressure?
Correct Answer: b) Barometer
Explanation:
A barometer is a scientific instrument used in meteorology to measure atmospheric pressure.
28. Water has its maximum density at what temperature?
Correct Answer: c) 4 degrees Celsius
Explanation:
Water has an anomalous property where it reaches its maximum density at approximately 4 degrees Celsius.
29. Who discovered the laws of planetary motion?
Correct Answer: c) Johannes Kepler
Explanation:
Johannes Kepler proposed the three laws of planetary motion in the early 17th century, describing the orbits of planets around the Sun.
30. Raindrops are spherical in shape due to:
Correct Answer: b) Surface tension
Explanation:
Surface tension is the tendency of liquid surfaces to shrink into the minimum surface area possible, causing small water drops to form spherical shapes.
31. What is the unit of electrical resistance?
Correct Answer: c) Ohm
Explanation:
The Ohm is the SI unit of electrical resistance, named after German physicist Georg Simon Ohm.
32. A transformer is used to:
Correct Answer: c) Step up or step down AC voltages
Explanation:
A transformer is an electrical device that transfers electrical energy between two or more circuits and is used to step up or step down alternating current (AC) voltage levels.
33. What is the approximate speed of light in a vacuum?
Correct Answer: b) 3 x 10^8 m/s
Explanation:
The speed of light in a vacuum is a fundamental physical constant exactly equal to 299,792,458 meters per second (approximately 3 x 10^8 m/s).
34. What is the chemical name of baking soda?
Correct Answer: b) Sodium bicarbonate
Explanation:
The chemical name of baking soda is sodium bicarbonate, with the formula NaHCO3.
35. What is the chemical name of washing soda?
Correct Answer: c) Sodium carbonate
Explanation:
Washing soda is chemically known as sodium carbonate decahydrate (Na2CO3.10H2O).
36. Plaster of Paris is made by heating:
Correct Answer: b) Gypsum
Explanation:
Plaster of Paris is prepared by heating gypsum (calcium sulfate dihydrate) to about 150 degrees Celsius, turning it into calcium sulfate hemihydrate.
37. Which acid is naturally secreted in the human stomach?
Correct Answer: c) Hydrochloric acid
Explanation:
The gastric glands in the human stomach secrete hydrochloric acid (HCl), which helps in the digestion of food and kills ingested pathogens.
38. Which of the following is the purest form of commercial iron?
Correct Answer: d) Wrought iron
Explanation:
Wrought iron is the purest commercial form of iron, containing less than 0.1% to 0.25% carbon.
39. Brass is an alloy of which two metals?
Correct Answer: b) Copper and Zinc
Explanation:
Brass is a metal alloy made primarily of copper and zinc. The proportions of zinc and copper can vary to create different types of brass.
40. Bronze is primarily an alloy of:
Correct Answer: b) Copper and Tin
Explanation:
Bronze is an alloy consisting primarily of copper, usually with about 12-12.5% tin and often with the addition of other metals.
41. Which is the lightest known metal?
Correct Answer: c) Lithium
Explanation:
Lithium is the lightest metal and the lightest solid element under standard conditions, with an atomic number of 3.
42. Which is the heaviest naturally occurring element on Earth?
Correct Answer: c) Uranium
Explanation:
Uranium (atomic number 92) is the heaviest naturally occurring element by atomic weight.
43. What is the most abundant element in the Earth's crust?
Correct Answer: b) Oxygen
Explanation:
Oxygen is the most abundant element in the Earth's crust, making up about 46.6% of its mass.
44. What is the most abundant metal in the Earth's crust?
Correct Answer: d) Aluminum
Explanation:
Aluminum is the most abundant metal in the Earth's crust, accounting for about 8.1% of it by mass.
45. Which metal remains liquid at room temperature?
Correct Answer: c) Mercury
Explanation:
Mercury is a heavy, silvery d-block element and is the only metallic element that is liquid at standard conditions for temperature and pressure.
46. Which non-metal is in a liquid state at room temperature?
Correct Answer: c) Bromine
Explanation:
Bromine is a halogen and the only non-metallic element that is a liquid at room temperature.
47. Which gas is primarily used in standard electric bulbs to prevent the oxidation of the tungsten filament?
Correct Answer: b) Argon
Explanation:
Argon, an inert gas, is filled in electric bulbs to provide an unreactive environment, which prevents the tungsten filament from burning up.
48. What is the common name for Nitrous oxide (N2O)?
Correct Answer: b) Laughing gas
Explanation:
Nitrous oxide is commonly known as laughing gas. It is often used as a mild anesthetic and analgesic in dentistry.
49. Which gas is commonly known as tear gas?
Correct Answer: b) Chloropicrin
Explanation:
Chloropicrin (or compounds like CS gas) is commonly used as a riot control agent and is referred to as tear gas.
50. Marsh gas primarily consists of:
Correct Answer: b) Methane
Explanation:
Marsh gas is a common name for methane (CH4), which is produced in marshes and swamps by the anaerobic decay of organic matter.
51. Which acid is the main active ingredient in vinegar?
Correct Answer: c) Acetic acid
Explanation:
Vinegar is an aqueous solution of acetic acid (ethanoic acid) and trace chemicals that may include flavorings.
52. Lemons and other citrus fruits contain mainly which acid?
Correct Answer: b) Citric acid
Explanation:
Citrus fruits like lemons, limes, and oranges are naturally rich sources of citric acid.
53. Which acid is abundantly found in tamarind and grapes?
Correct Answer: a) Tartaric acid
Explanation:
Tartaric acid is a naturally occurring organic acid that is found in many plants, especially grapes, bananas, and tamarinds.
54. The sting of ants and bees contains which acid?
Correct Answer: b) Formic acid
Explanation:
Formic acid (methanoic acid) is the simplest carboxylic acid and is found naturally in the venom of bee and ant stings.
55. What is the normal pH value of human blood?
Correct Answer: c) 7.4
Explanation:
The pH of normal human blood is slightly basic (alkaline), typically maintained in a very narrow range between 7.35 and 7.45.
56. Which isotope of hydrogen contains zero neutrons?
Correct Answer: c) Protium
Explanation:
Protium is the most common isotope of hydrogen. Its nucleus consists of only one proton and zero neutrons.
57. Who is known as the Father of Modern Chemistry?
Correct Answer: b) Antoine Lavoisier
Explanation:
Antoine Lavoisier is recognized as the Father of Modern Chemistry for his discovery of the role oxygen plays in combustion and his systematic naming of chemical compounds.
58. The atomic number of an element is determined by the number of:
Correct Answer: b) Protons in the nucleus
Explanation:
The atomic number uniquely identifies a chemical element and represents the number of protons found in the nucleus of an atom of that element.
59. The nucleus of an atom consists of:
Correct Answer: c) Protons and neutrons
Explanation:
The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom.
60. Who discovered the electron?
Correct Answer: c) J.J. Thomson
Explanation:
J.J. Thomson discovered the electron in 1897 through his experiments with cathode ray tubes.
61. Who is credited with the discovery of the proton?
Correct Answer: a) Ernest Rutherford
Explanation:
Ernest Rutherford is credited with the discovery of the proton in 1917, after observing that alpha particles could knock hydrogen nuclei out of nitrogen gas.
62. Who discovered the neutron in 1932?
Correct Answer: b) James Chadwick
Explanation:
Sir James Chadwick discovered the neutron, a subatomic particle with no net electric charge, in 1932.
63. Which element is common to all acids?
Correct Answer: c) Hydrogen
Explanation:
According to Arrhenius theory, an acid is a substance that dissociates in water to yield hydrogen ions (H+). Thus, hydrogen is common to all acids.
64. Which of the following gases is a major contributor to global warming?
Correct Answer: c) Carbon dioxide
Explanation:
Carbon dioxide is a greenhouse gas that traps heat in the atmosphere, making it a major contributor to global warming.
65. The rusting of iron is an example of which chemical process?
Correct Answer: b) Oxidation
Explanation:
Rusting of iron is an oxidation reaction where iron reacts with oxygen in the presence of water or moisture to form iron oxides.
66. What is dry ice chemically known as?
Correct Answer: c) Solid carbon dioxide
Explanation:
Dry ice is the solid form of carbon dioxide (CO2). It is used primarily as a cooling agent.
67. Which cell organelle is known as the powerhouse of the cell?
Correct Answer: c) Mitochondria
Explanation:
Mitochondria generate most of the chemical energy needed to power the cell's biochemical reactions, stored in a molecule called ATP.
68. Which organelles are referred to as the 'suicide bags' of a cell?
Correct Answer: c) Lysosomes
Explanation:
Lysosomes contain digestive enzymes that can break down cellular components or the entire cell itself if damaged, hence the term 'suicide bags'.
69. Which part of the cell is known as the protein factory?
Correct Answer: a) Ribosomes
Explanation:
Ribosomes are macromolecular machines responsible for biological protein synthesis (translation) in all living cells.
70. Which is the longest cell in the human body?
Correct Answer: b) Nerve cell (Neuron)
Explanation:
The nerve cell, or neuron, can be extremely long, with some running from the spinal cord down to the toes.
71. How many bones are there in a normal adult human body?
Correct Answer: a) 206
Explanation:
An adult human typically has 206 bones, while infants are born with around 300 bones that fuse together as they grow.
72. Which is the longest and strongest bone in the human body?
Correct Answer: c) Femur
Explanation:
The femur, or thigh bone, is the longest, heaviest, and strongest bone in the human body.
73. Which is the smallest bone in the human body?
Correct Answer: c) Stapes
Explanation:
The stapes is a tiny bone in the middle ear and is the smallest and lightest bone in the human body.
74. Biologically, blood is classified as which type of tissue?
Correct Answer: c) Connective tissue
Explanation:
Blood is considered a specialized form of connective tissue because it originates in the bones and connects the body systems by transporting materials.
75. Which blood group is known as the Universal Donor?
Correct Answer: c) O negative
Explanation:
O negative blood does not have A, B, or Rh antigens on the red blood cells, making it safe to transfuse to any blood type in emergencies.
76. Which blood group is known as the Universal Acceptor (Recipient)?
Correct Answer: b) AB positive
Explanation:
Individuals with AB positive blood have no A, B, or Rh antibodies in their plasma, meaning they can receive red blood cells of any type.
77. Where are red blood cells (RBCs) produced in the human body?
Correct Answer: d) Bone marrow
Explanation:
Red blood cells are continuously produced in the red bone marrow of large bones through a process called erythropoiesis.
78. What is the average lifespan of a human red blood cell?
Correct Answer: d) 120 days
Explanation:
A typical red blood cell has a lifespan of about 100 to 120 days before it is broken down by the spleen and liver.
79. What is the liquid matrix of the blood called?
Correct Answer: b) Plasma
Explanation:
Blood plasma is the yellowish liquid component of blood that holds the blood cells in whole blood in suspension.
80. What is considered a normal resting blood pressure for a healthy human adult?
Correct Answer: c) 120/80 mmHg
Explanation:
A normal blood pressure reading is usually around 120/80 mmHg, where 120 is the systolic pressure and 80 is the diastolic pressure.
81. Which gland is often referred to as the 'Master Gland' of the body?
Correct Answer: b) Pituitary gland
Explanation:
The pituitary gland is called the master gland because it produces hormones that control several other endocrine glands.
82. Which organ secretes the hormone insulin?
Correct Answer: c) Pancreas
Explanation:
Insulin is a hormone produced by the beta cells in the islets of Langerhans of the pancreas. It regulates the metabolism of carbohydrates.
83. Deficiency of Vitamin A causes which of the following diseases?
Correct Answer: b) Night blindness
Explanation:
Vitamin A is essential for healthy vision. A severe deficiency can lead to night blindness (nyctalopia) and other eye issues.
84. Beriberi is caused by the deficiency of which vitamin?
Correct Answer: a) Vitamin B1 (Thiamine)
Explanation:
Beriberi is a disease caused by a vitamin B1 (thiamine) deficiency. It affects the cardiovascular or nervous system.
85. Scurvy is a disease resulting from a deficiency of:
Correct Answer: c) Vitamin C
Explanation:
Scurvy is caused by a severe and chronic deficiency of vitamin C (ascorbic acid), which is necessary for collagen synthesis.
86. Rickets in children is primarily caused by a lack of which vitamin?
Correct Answer: c) Vitamin D
Explanation:
Rickets is a condition that results in weak or soft bones in children. It is most commonly caused by a lack of vitamin D, calcium, or phosphorus.
87. Which of the following vitamins are water-soluble?
Correct Answer: b) Vitamins B and C
Explanation:
Vitamins B (complex) and C are water-soluble. They dissolve in water and are not stored in the body, meaning they need constant replenishment.
88. Which group of vitamins are fat-soluble?
Correct Answer: b) Vitamins A, D, E, K
Explanation:
Vitamins A, D, E, and K are fat-soluble vitamins. They are absorbed along with fats in the diet and can be stored in the body's fatty tissue.
89. The scientific study of cells is called:
Correct Answer: b) Cytology
Explanation:
Cytology is the branch of biology concerned with the structure and function of plant and animal cells.
90. Histology is the study of:
Correct Answer: c) Tissues
Explanation:
Histology, also known as microscopic anatomy, is the branch of biology that studies the microscopic anatomy of biological tissues.
91. Which viral disease is most commonly transmitted through the bite of an infected animal, like a dog?
Correct Answer: c) Rabies
Explanation:
Rabies is a deadly viral disease that is most frequently transmitted to humans through the bite or scratch of an infected animal.
92. Malaria in humans is caused by which type of pathogen?
Correct Answer: d) Protozoa
Explanation:
Malaria is caused by Plasmodium parasites, which are microscopic single-celled organisms classified as protozoa.
93. Which mosquito is the vector responsible for transmitting malaria?
Correct Answer: c) Female Anopheles
Explanation:
Malaria is transmitted primarily by the bite of infective female Anopheles mosquitoes, which carry the Plasmodium parasite.
94. Dengue fever is caused by a:
Correct Answer: b) Virus
Explanation:
Dengue fever is a mosquito-borne tropical disease caused by the dengue virus, which is spread by Aedes mosquitoes.
95. Typhoid fever primarily affects which part of the human body?
Correct Answer: c) Intestines
Explanation:
Typhoid is a bacterial infection caused by Salmonella Typhi. It primarily affects the intestines, causing high fever and gastrointestinal issues.
96. Tuberculosis (TB) is a disease caused by a:
Correct Answer: b) Bacterium
Explanation:
Tuberculosis is an infectious disease usually caused by the bacterium Mycobacterium tuberculosis, primarily affecting the lungs.
97. What is the biological process by which green plants make their own food?
Correct Answer: c) Photosynthesis
Explanation:
Photosynthesis is the process used by plants, algae, and certain bacteria to harness energy from sunlight and turn it into chemical energy.
98. Which gas is absorbed by plants from the atmosphere during photosynthesis?
Correct Answer: c) Carbon dioxide
Explanation:
During photosynthesis, plants take in carbon dioxide from the air and water from the soil to create glucose, releasing oxygen as a byproduct.
99. Which pigment is responsible for the green color of leaves and absorbs light energy for photosynthesis?
Correct Answer: c) Chlorophyll
Explanation:
Chlorophyll is the green pigment found in the chloroplasts of plants, which is essential for capturing the light energy needed for photosynthesis.
100. Which metal ion is centrally present in the chlorophyll molecule?
Correct Answer: d) Magnesium
Explanation:
The core of the chlorophyll molecule is a porphyrin ring with a single atom of magnesium at its center.
