Railway recruitment covers several exams with overlapping syllabi, so one round of preparation serves RRB NTPC, Group D, ALP, Junior Engineer and Technician. Questions here cover mathematics, general intelligence and reasoning, general science, and general awareness including current affairs. The science section is pitched at the level the RRB papers use, which is closer to school syllabus than to competitive exam theory.
Which element is the most abundant in the Earth's atmosphere?
Answer: B
Nitrogen comprises about 78% of Earth's atmosphere, followed by oxygen at about 21%.
Q.22Medium
What is the principal source of energy for the Earth?
Answer: B
The Sun is the primary source of energy for Earth, providing energy through radiation that drives weather, climate, and photosynthesis.
Q.23Medium
Which of the following is an example of a physical change?
Answer: C
Melting of ice is a physical change as water remains H₂O but changes from solid to liquid state. Other options are chemical changes.
Q.24Medium
In Newton's third law of motion, if object A exerts a force on object B, what does object B do?
Answer: A
Newton's third law states that for every action, there is an equal and opposite reaction. Forces always occur in pairs.
Q.25Medium
Which of the following is the largest organ in the human body by mass?
Answer: C
The liver is the largest internal organ by mass, weighing approximately 1.5 kg in adults.
Q.26Medium
What happens to the density of water when it freezes into ice?
Answer: B
Ice has lower density than water, which is why ice floats on water. Water expands when it freezes.
Q.27Medium
Which of the following is NOT a type of simple machine?
Answer: C
A turbine is not a simple machine. The six simple machines are lever, pulley, inclined plane, wedge, screw, and wheel-axle.
Q.28Medium
What is the primary component of natural gas?
Answer: C
Methane (CH4) is the primary component of natural gas, making up about 70-90% of its composition.
Q.29Medium
Which blood cell is responsible for carrying oxygen throughout the body?
Answer: B
Red blood cells (erythrocytes) contain hemoglobin and transport oxygen from lungs to body tissues.
Q.30Medium
What is the process by which a liquid changes into a solid?
Answer: B
Freezing is the phase change from liquid to solid, typically occurring at the freezing point of a substance.
Q.31Medium
Which of the following diseases is caused by a deficiency of Vitamin C?
Answer: B
Scurvy is caused by vitamin C deficiency, leading to weak connective tissue and poor wound healing.
Q.32Medium
Which of the following is an example of a conductor?
Answer: B
Copper is an excellent electrical conductor that allows electricity to flow through it easily. Rubber, glass, and plastic are insulators.
Q.33Medium
What is the percentage of oxygen in the Earth's atmosphere?
Answer: B
Oxygen comprises approximately 21% of Earth's atmosphere. Nitrogen makes up about 78%, with other gases comprising the remainder.
Q.34Medium
Which disease is caused by iodine deficiency?
Answer: B
Goiter is caused by insufficient iodine in the diet, leading to thyroid gland enlargement. Iodine is essential for thyroid hormone production.
Q.35Medium
What is the SI unit of electrical current?
Answer: C
The Ampere (A) is the SI unit of electrical current, named after physicist André-Marie Ampère.
Q.36Medium
Which planet in our solar system has the most moons?
Answer: B
Jupiter has 95 confirmed moons (as of 2024), making it the planet with the most moons in our solar system.
Q.37Medium
What is the process of conversion of iron into rust primarily called?
Answer: C
Corrosion is the process of rust formation. Iron oxidation in the presence of moisture and oxygen leads to rust (Fe2O3).
Q.38Medium
Which gland produces insulin in the human body?
Answer: B
The pancreas produces insulin, a hormone that regulates blood glucose levels. Beta cells in the pancreas secrete insulin.
Q.39Medium
Which of the following best describes the process of photosynthesis?
Answer: B
Photosynthesis is the process by which plants convert light energy into chemical energy in the form of glucose, using carbon dioxide and water. The overall equation is 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.
Q.40Medium
Which of the following is an endothermic reaction?
Answer: B
Melting of ice is an endothermic reaction as it requires absorption of heat energy. Combustion and rusting are exothermic reactions that release heat; condensation is also exothermic.
