Q41. The primary mechanism of heat transfer in solid metals is:
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.
Showing 41–50 of 1113 questions
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Q42. Which mode of heat transfer does not require any material medium?
Explanation
Radiation is a mode of heat transfer that utilizes electromagnetic waves to transport energy. Unlike conduction and convection, it does not require a physical medium like a solid, liquid, or gas to move through. This is why heat from the Sun can travel through the vast vacuum of space to reach the Earth, providing the energy necessary for life and climate systems.
Q43. Absolute zero is mathematically equivalent to which of the following temperatures on the Celsius scale?
Explanation
Absolute zero is the lowest theoretical temperature where all molecular motion ceases. On the Kelvin scale, this point is defined as zero K. To convert this to the Celsius scale, one must subtract two hundred and seventy-three point one five. Therefore, absolute zero corresponds to negative two hundred and seventy-three point one five degrees Celsius, representing the absolute limit of coldness.
Q44. The anomalous expansion of water occurs between which temperature range?
Explanation
Most substances contract when cooled, but water exhibits a unique behavior called anomalous expansion between zero and four degrees Celsius. As water is heated from zero degrees, its density increases and its volume decreases until it reaches four degrees. This property is vital for aquatic life, as it ensures that the densest water sinks to the bottom, preventing lakes from freezing solid.
Q45. Given below are two statements: one is labelled as Assertion (A) and the other is labelled as
Reason (R).
Assertion (A): Water is often used as a coolant in automobile radiators.
Reason (R): Water has a very high specific heat capacity compared to most other liquids.
Reason (R).
Assertion (A): Water is often used as a coolant in automobile radiators.
Reason (R): Water has a very high specific heat capacity compared to most other liquids.
Explanation
Water possesses an exceptionally high specific heat capacity, meaning it can absorb a large amount of heat energy with only a small increase in its own temperature. This property makes it an ideal coolant for automobile engines. By circulating through the radiator, water effectively removes excess thermal energy generated during combustion, preventing the engine from overheating while maintaining stable operating temperatures.
Q46. The amount of heat energy required to change 1 kg of a solid into a liquid at atmospheric pressure at its melting point is known as:
Explanation
The latent heat of fusion is the specific amount of thermal energy required to change a substance from its solid state to a liquid state without changing its temperature. This process occurs at the melting point under constant atmospheric pressure. The energy is used to break the molecular bonds within the solid lattice rather than increasing the kinetic energy of the particles themselves.
Q47. Sea breezes and land breezes are natural phenomena primarily caused by:
Explanation
Sea and land breezes are driven by differential heating between land and water. Land heats up and cools down faster than the ocean. During the day, warm air over the land rises, creating a low-pressure area that pulls in cooler air from the sea. This movement of air, known as a convection current, reverses at night as the land cools more rapidly.
Q48. Mercury is commonly used in clinical thermometers because it:
Explanation
Mercury is favored for use in clinical thermometers because it expands uniformly across a wide range of temperatures, ensuring accurate readings. As a metal, it is a good conductor of heat and responds quickly to changes. Furthermore, its silver color makes it easy to see against the glass, and it does not wet or stick to the capillary tube’s internal surface.
Q49. Which of the following surfaces is the best emitter of thermal radiation?
Explanation
The ability of a surface to emit thermal radiation is closely related to its ability to absorb it. According to Kirchhoff’s law, good absorbers are also good emitters. Dark, rough, or matte surfaces absorb almost all incident radiation and emit thermal energy much more efficiently than light-colored, smooth, or polished surfaces, which tend to reflect radiation instead of absorbing it.
Q50. When salt is added to pure water, its boiling point:
Explanation
Adding a non-volatile solute like salt to pure water causes a phenomenon known as boiling point elevation. The salt particles interfere with the water molecules’ ability to escape into the vapor phase, requiring more thermal energy to reach a vapor pressure equal to the atmospheric pressure. Consequently, the temperature at which the solution boils is higher than that of pure water alone.Answer key for these questions
| Q | Correct answer |
|---|---|
| 41 | (c) Conduction |
| 42 | (a) Radiation |
| 43 | (c) -273.15 degrees Celsius |
| 44 | (a) 0 to 4 degrees Celsius |
| 45 | (a) Both A and R are true and R is the correct explanation of A. |
| 46 | (d) Latent heat of fusion |
| 47 | (a) Convection currents in the atmosphere |
| 48 | (b) expands uniformly across a wide temperature range |
| 49 | (b) A rough black surface |
| 50 | (b) Increases |
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.