Q21. According to the universal law of gravitation, the force between two objects is inversely proportional to:
Science and Technology: RAS Prelims MCQs
1113 RAS Prelims practice MCQs on science and technology are on this page, in 6 chapters. They cover the basics of everyday science, computers and information technology, defence and space technology in India, genetics, biotechnology and nanotechnology, science and technology policies and government programmes, and recent advances with Indian contributors and indigenisation. Each question has an answer and an explanation.
Practice questions based on the RPSC RAS Prelims syllabus. They follow the exam pattern but are not past-paper questions.
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Q22. Consider the following statements about mass and weight:
I. Mass is a scalar quantity, while weight is a vector quantity.
II. The mass of a body remains constant everywhere in the universe.
III. Weight is the gravitational force acting on an object.
IV. A body can have zero mass but non-zero weight in space.
Which of the above statement(s) is/are correct?
I. Mass is a scalar quantity, while weight is a vector quantity.
II. The mass of a body remains constant everywhere in the universe.
III. Weight is the gravitational force acting on an object.
IV. A body can have zero mass but non-zero weight in space.
Which of the above statement(s) is/are correct?
Explanation
Mass is a fundamental scalar property representing the amount of matter in an object and remains constant regardless of location. Weight is a vector quantity representing the gravitational force acting on that mass and varies based on gravity’s strength. While weight can become zero in certain conditions, such as deep space, mass can never be zero for any physical object or body.
Q23. The acceleration due to gravity (g) on the surface of the Earth is maximum at:
Explanation
Acceleration due to gravity varies across the Earth’s surface due to its flattened shape and rotation. The planet is an oblate spheroid, meaning the distance from the center to the surface is shortest at the poles. Because gravitational pull is stronger when closer to the center, the value of g reaches its maximum at the poles and its minimum at the equator.
Q24. When an object undergoes free fall near the Earth’s surface (ignoring air resistance), its:
Explanation
During free fall in a vacuum near the Earth’s surface, all objects experience a constant acceleration due to gravity, approximately 9.8 meters per second squared. While the velocity of the falling object increases uniformly over time, the rate at which it speeds up remains the same. Air resistance is ignored in this idealized model to focus on pure gravitational influence on motion.
Q25. The minimum initial velocity required for an object to escape the Earth’s gravitational pull is approximately:
Explanation
Escape velocity is the minimum speed an object must reach to break free from a planet’s gravitational field without further propulsion. For Earth, this value is approximately 11.2 kilometers per second. If an object is launched at this speed, its kinetic energy will exactly balance its gravitational potential energy, allowing it to move infinitely far away from the Earth’s pull.
Q26. Who was the first scientist to experimentally determine the value of the universal gravitational constant (G)?
Explanation
Henry Cavendish was the first scientist to accurately measure the value of the universal gravitational constant, known as G, using a torsion balance. His famous 1798 experiment allowed for the calculation of the Earth’s density and mass. While Isaac Newton formulated the law of universal gravitation, he did not experimentally determine the specific value of the constant required for calculations.
Q27. Astronauts in low Earth orbit experience "weightlessness" because:
Explanation
Astronauts in orbit experience weightlessness not because gravity is absent, but because they and their spacecraft are in a state of continuous free fall towards Earth. As they move forward at high speed, the planet’s surface curves away at the same rate they fall. This creates an environment where no normal force acts between the astronauts and their surroundings.
Q28. Consider the following planets:
I. Jupiter
II. Mars
III. Earth
Which of the following represents the correct arrangement of these planets in increasing order of their surface gravity?
I. Jupiter
II. Mars
III. Earth
Which of the following represents the correct arrangement of these planets in increasing order of their surface gravity?
Explanation
Surface gravity depends on a planet’s mass and radius. Mars has a lower mass than Earth, resulting in weaker gravitational pull. Jupiter, being the most massive planet in the solar system, possesses the strongest surface gravity among the three. Therefore, the correct sequence from the weakest to the strongest gravitational force is Mars, followed by Earth, and then Jupiter as the highest.
Q29. Kepler’s second law of planetary motion, the law of equal areas, is a consequence of the conservation of:
Explanation
Kepler’s second law states that a line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time. This phenomenon is a direct consequence of the conservation of angular momentum in a central force field. As a planet moves closer to the Sun, its orbital speed increases to ensure its total angular momentum remains constant throughout its orbit.
Q30. Which of the following is an exception to the rule that all massive bodies fall at the same rate in a vacuum?
Explanation
In a vacuum, where air resistance is absent, all objects experience the same acceleration due to gravity regardless of their mass or shape. This principle, famously demonstrated by Galileo, confirms that a feather and a heavy coin will hit the ground simultaneously when dropped from the same height. Therefore, there are no exceptions to this rule in a truly friction-free environment.Answer key for these questions
| Q | Correct answer |
|---|---|
| 21 | (c) The square of distance between their centers |
| 22 | (a) I, II and III |
| 23 | (d) The poles |
| 24 | (a) Acceleration remains constant |
| 25 | (b) 11.2 km/s |
| 26 | (a) Henry Cavendish |
| 27 | (d) They are in a constant state of free fall towards the Earth |
| 28 | (a) II, III, I |
| 29 | (c) Angular momentum |
| 30 | (d) There is no exception; all objects fall at the same rate in a vacuum |
Key facts from Science and Technology
- The RPSC paper is General Knowledge and General Science, so science questions come with a strong dose of applied and recent topics.
- Everyday science questions test the laws and terms of physics, chemistry and biology through examples.
- Defence and space questions pair a missile, satellite or mission with its year and organisation.
- Policy questions ask for the year, the body and the aim of schemes like STIP, the National Quantum Mission and BioE3.
- Health, environment and agriculture are on a separate page, with their own chapters.
Frequently asked questions
How many RAS Prelims practice MCQs are there on Science and Technology?
This page has 1113 practice MCQs on Science and Technology. Each has the correct answer, and most have an explanation.
Which chapters does the science and technology set cover?
Six chapters: basics of everyday science; computers, information and communication technology; defence and space technology in India; genetics, biotechnology and nanotechnology; science and technology policies and government programmes; and recent advances, Indian contributors and indigenisation.
Is science and technology part of the RAS Prelims syllabus?
Yes. The RPSC paper is called General Knowledge and General Science, and its syllabus lists science and technology topics along with environment, health, agriculture and government programmes, so questions can come from any of these areas.
How should I prepare science for RAS Prelims?
Revise the concepts by examples, then learn the missions, schemes and scientists with their year and organisation. Attempt each chapter, read the explanations and keep a list of the facts you missed.