Q651. Which of the following synthetic fibers is often referred to as "artificial silk" because it is regenerated from natural cellulose?
RAS Prelims MCQ Practice
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.
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Q652. Brass is an alloy primarily composed of which two metals?
Explanation
Brass is a versatile metallic alloy primarily composed of copper and zinc. By varying the proportions of these two metals, manufacturers can create different types of brass with specific mechanical and electrical properties. It is widely used in musical instruments, decorative hardware, and plumbing fixtures due to its attractive gold-like appearance, excellent workability, and high resistance to corrosion and wear.
Q653. Bronze is a historically significant alloy made mostly of:
Explanation
Bronze is a historically significant alloy that consists primarily of copper, with tin as the main additive. Other elements may be added to enhance specific properties. Bronze is harder and more durable than pure copper and is highly resistant to corrosion, especially from seawater. This made it the preferred material for ancient tools, statues, and modern industrial components like ship propellers.
Q654. Select the correct sequence of the following fibers arranged in increasing order of their typical tensile strength:
Explanation
Tensile strength measures the maximum stress a material can withstand while being stretched. Among these common fibers, wool generally has the lowest tensile strength. Cotton, a natural plant fiber, is significantly stronger than wool. Nylon, a fully synthetic polymer, is engineered for extreme durability and possesses the highest tensile strength of the three, making it ideal for products like ropes and parachutes.
Q655. Kevlar, a high-strength synthetic polymer, is best known for its use in:
Explanation
Kevlar is a high-performance synthetic fiber belonging to the aramid family. It is renowned for its exceptional tensile strength-to-weight ratio, being five times stronger than steel on an equal weight basis. Its unique molecular structure allows it to absorb and dissipate energy from high-velocity impacts, making it the primary material used in the manufacture of bulletproof vests and personal protective equipment.
Q656. Fiberglass is an example of a composite material where glass fibers are embedded in a:
Explanation
Fiberglass is a type of composite material where extremely fine fibers of glass are used as a reinforcement. These fibers are embedded within a liquid polymer matrix, typically a plastic resin, which is then cured into a solid. The resulting material combines the high tensile strength of the glass fibers with the flexibility and lightweight nature of the plastic, creating a durable product.
Q657. The principal raw material used in the manufacture of ordinary glass is:
Explanation
Silica, commonly found in the form of quartz sand, is the fundamental raw material used in the production of ordinary glass. To lower the high melting point of pure silica, other substances like sodium carbonate and limestone are typically added. When heated to high temperatures, this mixture melts into a liquid that, upon cooling, forms the transparent, amorphous solid we know as glass.
Q658. The most abundant chemical compound in Portland cement is:
Explanation
Portland cement is a complex mixture of several chemical compounds, but calcium oxide, also known as lime, is the most abundant constituent, typically making up over sixty percent of its weight. Other important ingredients include silica, alumina, and iron oxide. These compounds are produced by heating a precisely proportioned mixture of limestone and clay in a kiln for construction applications.
Q659. Why are synthetic detergents generally preferred over traditional soaps for washing clothes in hard water?
Explanation
Hard water contains high concentrations of dissolved minerals, such as calcium and magnesium ions. Traditional soaps react with these ions to form an insoluble, sticky precipitate known as scum, which reduces cleaning efficiency. Synthetic detergents, however, are specifically formulated so their salts are soluble in water even in the presence of these minerals, allowing them to lather easily in hard water.
Q660. Consider the following statements about bleaching powder (Calcium oxychloride):
I. It is produced by the action of chlorine gas on dry slaked lime.
II. It is used for disinfecting drinking water.
III. It releases oxygen gas when left open in the air.
Which of the above statement(s) is/are correct?
I. It is produced by the action of chlorine gas on dry slaked lime.
II. It is used for disinfecting drinking water.
III. It releases oxygen gas when left open in the air.
Which of the above statement(s) is/are correct?
Explanation
Bleaching powder is produced by reacting chlorine gas with dry slaked lime, a process that yields calcium oxychloride. It is highly effective as a disinfectant for treating drinking water and as a bleaching agent in textiles. However, it does not release oxygen when exposed to air; instead, it reacts with atmospheric carbon dioxide to slowly release chlorine gas, providing its pungent odor.Answer key for these questions
| Q | Correct answer |
|---|---|
| 651 | (c) Rayon |
| 652 | (d) Copper and Zinc |
| 653 | (a) Copper and Tin |
| 654 | (b) Wool < Cotton < Nylon |
| 655 | (b) Bulletproof vests and body armor |
| 656 | (a) Polymer or plastic matrix |
| 657 | (c) Silica (sand) |
| 658 | (d) Calcium oxide (CaO) |
| 659 | (c) They do not form scum in hard water |
| 660 | (a) I and II only |
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.