9,654 RAS Prelims practice MCQs with the correct answer and a clear explanation for each. Filter by subject and chapter.
Practice questions based on the RPSC RAS Prelims syllabus. They follow the exam pattern but are not past-paper questions.
Showing 1941–1950 of 9654 questions
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RAS PrelimsScience and Technology · Defence and Space Technology in India
Q1941. Consider the following statements: Statement I: The Vikas engine is a liquid-fueled rocket engine used in the second stage of PSLV and GSLV. Statement II: The Vikas engine relies on liquid oxygen and liquid hydrogen as propellants. Which of the above statement(s) is/are correct?
Explanation
This reliable liquid-fueled engine is a critical component of several major rockets used by the space agency. It provides the necessary power for the second stages of these vehicles. However, it does not use the extremely cold fuels typical of cryogenic engines. Instead, it relies on propellants that can be stored at normal temperatures. This engine has a long history of successful flights and remains a cornerstone of the country’s liquid propulsion technology and satellite launch capacity.
RAS PrelimsScience and Technology · Defence and Space Technology in India
Q1942. The design architecture of the Launch Vehicle Mark-3 (LVM3) consists of:
Explanation
The design of this heavy launcher is built around a central liquid-fueled stage that is assisted by two massive solid rocket motors attached to its sides. For the final phase of its journey, it uses a sophisticated high-performance engine that runs on extremely cold liquid fuels. This three-stage configuration provides the immense thrust needed to carry heavy communication satellites or human-rated capsules into space. It represents the most powerful and advanced launch system currently in the national inventory.
RAS PrelimsScience and Technology · Defence and Space Technology in India
Q1943. Which of the following is a negative statement regarding the operational history of the PSLV?
Explanation
While this rocket eventually became legendary for its reliability and success, its initial test flight did not go as planned. In 1993, the first attempt to launch the vehicle ended in failure due to a technical error. However, the agency quickly identified the problem and fixed it, leading to an incredibly successful career. Since then, it has launched famous missions to the moon and Mars, proving itself as one of the most dependable rockets in the world.
RAS PrelimsScience and Technology · Defence and Space Technology in India
Q1944. The PSLV has earned its reputation primarily by placing earth observation and remote sensing satellites into which specific orbit?
Explanation
This rocket is primarily used to place Earth observation and remote sensing satellites into a specific high-latitude orbit. In this path, the satellite passes over the poles and stays in a constant position relative to the sun. This is ideal for imaging and monitoring the planet’s surface under consistent lighting conditions. The rocket’s precision in reaching this orbit has made it the global leader for such missions, serving both national needs and international commercial clients successfully for decades.
RAS PrelimsScience and Technology · Defence and Space Technology in India
Q1945. Identify the odd one out among the rocket engines/motors used by ISRO:
Explanation
This specific engine is a high-performance liquid-fueled motor developed by a private American aerospace company for its own line of rockets. It is not part of the technology used by the national space agency, which relies on its own indigenous designs like the Vikas and cryogenic motors. The other listed items are all well-known components used in the country’s various satellite launch vehicles, making the foreign-developed engine the clear exception in this group of propulsion systems.
RAS PrelimsScience and Technology · Defence and Space Technology in India
Q1946. Consider the following statements regarding the Chandrayaan-1 mission: I. It was launched in 2008 using the PSLV-C11. II. It included a Moon Impact Probe (MIP) that crash-landed near the lunar south pole. III. It definitively discovered evidence of water molecules on the lunar surface. Which of the above statement(s) is/are correct?
Explanation
The first lunar mission was launched in 2008 and successfully placed a spacecraft in orbit around the moon. It included a specialized probe that intentionally impacted the surface to study its composition. A major scientific achievement of this mission was the definitive detection of water molecules on the lunar surface, changing our understanding of the moon. These results were verified by multiple instruments and international partners, marking a major milestone for the national space program and global lunar science.
RAS PrelimsScience and Technology · Defence and Space Technology in India
Q1947. The following question consists of two statements, Assertion (A) and Reason (R). Answer the question by selecting the appropriate option. Assertion (A): The Chandrayaan-2 mission is often described as partially successful. Reason (R): While the Vikram lander crashed during the final descent, the Orbiter was successfully placed in lunar orbit and continues to send valuable scientific data.
Explanation
This complex mission had multiple components, and while one part failed, others were highly successful. The attempt to land a vehicle on the surface did not go as planned, resulting in a crash. However, the orbiting spacecraft was placed perfectly in lunar orbit and has continued to provide high-resolution images and scientific data for many years. Because of this mix of outcomes, the mission is recognized for its significant contributions despite the loss of the landing vehicle.
RAS PrelimsScience and Technology · Defence and Space Technology in India
Q1948. The critical instrument on Chandrayaan-1 that helped discover water on the Moon, the Moon Mineralogy Mapper (M3), was contributed by:
Explanation
This sophisticated instrument was one of the key payloads on the first lunar mission and was provided by the American space agency. It was specifically designed to map the minerals on the moon’s surface and was instrumental in the discovery of water molecules. This collaboration highlights the international nature of space exploration and how different countries can work together to achieve major scientific breakthroughs. The data from this instrument provided a new perspective on the history and geology of the moon.
RAS PrelimsScience and Technology · Defence and Space Technology in India
Q1949. Which launch vehicle was used to launch the Chandrayaan-2 mission in 2019?
Explanation
For this ambitious mission involving an orbiter, a lander, and a rover, the country’s most powerful rocket was required. This heavy-lift vehicle successfully carried the large and complex spacecraft through the initial stages of its journey to the moon. Its ability to place such a heavy payload into a precise transfer orbit was a demonstration of the growing maturity of the nation’s heavy launch technology. This rocket has since become the primary choice for deep space and manned missions.
RAS PrelimsScience and Technology · Defence and Space Technology in India
Q1950. Consider the following statements: Statement I: The primary reason for the failure of the Chandrayaan-2 lander was a software glitch that caused loss of control during the fine braking phase. Statement II: Chandrayaan-3 utilized the exact same lander design and software algorithms as Chandrayaan-2 without modifications. Which of the above statement(s) is/are correct?
Explanation
The failure of the previous landing attempt was traced to a software issue during the final descent phase. For the subsequent mission, significant changes were made to both the hardware and the software to ensure success. This included strengthening the landing legs and updating the control algorithms to handle a wider range of conditions. Suggestions that the later mission used an identical design without any modifications are incorrect, as those changes were critical to the successful landing near the south pole.
Answer key for these questions
Q
Correct answer
1941
(a) Statement I is correct but Statement II is incorrect.
1942
(a) Two solid strap-on boosters, a core liquid stage, and a cryogenic upper stage.
1943
(b) It failed its very first developmental flight in 1993.
1944
(b) Sun-Synchronous Polar Orbit
1945
(a) Merlin
1946
(d) I, II, and III
1947
(a) Both A and R are true and R is the correct explanation of A.
1948
(c) NASA (USA)
1949
(b) GSLV Mk III (LVM3)
1950
(a) Statement I is correct but Statement II is incorrect.
Frequently asked questions
How many RAS Prelims practice MCQs are there on RAS Prelims?
This page has 9654 practice MCQs on the RAS Prelims syllabus. Each has the correct answer, and most have an explanation.
How should I practise MCQs for RAS Prelims?
Attempt each question first, then open the answer and read the explanation. Practise one chapter at a time, note the facts you got wrong and revise them. Repeat the chapter after a few days.
Are these actual RAS Prelims past-paper questions?
No. These are practice questions written for the RAS Prelims syllabus. They follow the pattern the exam uses: factual questions, statement-based questions, match-the-list and assertion-reason.
