UPSC CAPF Archives

11. X is twice as massive as Y. X also runs twice faster than Y. Which one

X is twice as massive as Y. X also runs twice faster than Y. Which one among the following is the ratio of kinetic energy of X and Y ?

1 : 8

8 : 1

4 : 1

2 : 1

This question was previously asked in

UPSC CAPF – 2010

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The ratio of kinetic energy of X and Y is 8 : 1.

The kinetic energy (KE) of an object is given by the formula KE = ½ * m * v², where m is the mass and v is the velocity. Given that the mass of X (m_X) is twice the mass of Y (m_Y), so m_X = 2 * m_Y. Also, the velocity of X (v_X) is twice the velocity of Y (v_Y), so v_X = 2 * v_Y.
KE_X = ½ * m_X * v_X² = ½ * (2 * m_Y) * (2 * v_Y)² = ½ * 2 * m_Y * 4 * v_Y² = 8 * (½ * m_Y * v_Y²)
KE_Y = ½ * m_Y * v_Y²
The ratio KE_X / KE_Y = [8 * (½ * m_Y * v_Y²)] / [½ * m_Y * v_Y²] = 8 / 1. Thus, the ratio is 8:1.

Kinetic energy is a scalar quantity representing the energy of motion. It is directly proportional to the mass of the object and the square of its velocity. Doubling the velocity has a much greater impact on kinetic energy than doubling the mass.

12. Which among the following is/are the reasons behind using Mercury in t

Which among the following is/are the reasons behind using Mercury in thermometers ?

1. Mercury does not wet the inner sides of the thermometer.
2. It can be seen easily in a thin capillary tube of the thermometer.
3. It is a good conductor of heat.
4. It is non-toxic.

Select the correct answer using the code given below :

1 only

1 and 2 only

1, 2 and 3

3 and 4

This question was previously asked in

UPSC CAPF – 2010

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The reasons behind using Mercury in thermometers among the given options are that Mercury does not wet the inner sides of the thermometer, it can be seen easily in a thin capillary tube, and it is a good conductor of heat.

Mercury possesses several properties suitable for use in thermometers: 1) It has high surface tension and does not wet (stick to) the glass tube, allowing for accurate readings of the meniscus. 2) It is opaque and reflective, making the column easily visible against the glass. 3) It is a good conductor of heat, which facilitates faster transfer of heat from the object being measured to the mercury, allowing it to quickly reach thermal equilibrium. 4) Mercury is highly toxic, which is a disadvantage, not a reason for its use.

Other properties of mercury that make it suitable for thermometers include a relatively low freezing point (-38.83 °C) and a high boiling point (356.73 °C), giving it a wide range of use, and a uniform coefficient of thermal expansion within its liquid range. However, due to its toxicity, mercury thermometers are being increasingly replaced by alcohol-based or digital thermometers.

13. Consider the following items of wholesale price index : 1. Primary

Consider the following items of wholesale price index :

1. Primary articles
2. Fuel, power, lights and lubricants
3. Manufacturing products

Arrange the above items in descending order in terms of their weightage in calculating wholesale price index :

1, 2, 3

1, 3, 2

3, 1, 2

3, 2, 1

This question was previously asked in

UPSC CAPF – 2010

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Arranging the items in descending order of their weightage in calculating the Wholesale Price Index (WPI) gives: Manufacturing products, Primary articles, Fuel, power, lights and lubricants.

The Wholesale Price Index (WPI) in India is calculated based on the weighted average of prices of a basket of commodities. The commodities are classified into three major groups with different weightages reflecting their relative importance in wholesale trade. As per the current series (Base Year 2011-12), the weightages are approximately: Manufactured Products (64.23%), Primary Articles (22.62%), and Fuel & Power (13.15%). While the exact percentages may vary slightly with base year revisions, the descending order of weightage consistently remains Manufacturing > Primary > Fuel & Power.

WPI measures the average change in the prices of commodities at the wholesale level. It is primarily used as a macroeconomic indicator for monitoring inflation, formulating trade and fiscal policies, and in business decisions like price negotiation and escalation clauses. The base year for WPI is revised periodically to reflect changes in the structure of the economy.

14. Which of the following is/are the methods of prevention from HIV infec

Which of the following is/are the methods of prevention from HIV infection ?

1. Use of condoms.
2. Use of intra-uterine devices like Copper-T.
3. Staying away from HIV infected person.
4. Using a face mask when in company of HIV infected person.

Select the correct answer using the code given below :

1 and 2 only

3 and 4

1, 2 and 4

1 only

This question was previously asked in

UPSC CAPF – 2010

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Among the given options, the use of condoms is a method of prevention from HIV infection.

Using condoms correctly and consistently during sexual activity significantly reduces the risk of HIV transmission. Intra-uterine devices (like Copper-T) are contraceptives and do not prevent HIV or other sexually transmitted infections (STIs). Staying away from an HIV-infected person is not necessary for prevention as HIV is not transmitted through casual contact. Using a face mask is irrelevant as HIV is not an airborne virus.

Other effective methods for preventing HIV transmission include abstinence, reducing the number of sexual partners, consistent and correct use of condoms, pre-exposure prophylaxis (PrEP), post-exposure prophylaxis (PEP), using sterile needles for injection, and safe blood transfusion practices. Antiretroviral therapy (ART) can also reduce the viral load in infected individuals to undetectable levels, effectively preventing sexual transmission (Undetectable = Untransmittable, U=U).

15. Which of the following are the risk factors in the transmission of the

Which of the following are the risk factors in the transmission of the HIV infection ?

1. Smoking and drinking alcohol
2. Observing bad hygiene
3. Blood transfusion
4. Unprotected sex

Select the correct answer using the code given below :

1 and 3 only

3 and 4 only

1, 3 and 4

1, 2 and 4

This question was previously asked in

UPSC CAPF – 2010

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The risk factors in the transmission of the HIV infection among the given options are Blood transfusion and Unprotected sex.

HIV is transmitted through specific bodily fluids: blood, semen, vaginal secretions, rectal fluids, and breast milk. Transmission routes primarily involve unprotected sexual contact (vaginal, anal, oral), sharing of needles or syringes, blood transfusions (rare in countries with screening), and from mother to child during pregnancy, childbirth, or breastfeeding. Smoking, drinking alcohol, and general bad hygiene are not direct routes of HIV transmission.

HIV is not transmitted through casual contact like touching, hugging, kissing, sharing utensils, using the same toilet, or mosquito bites. Understanding the actual transmission routes is crucial for prevention.

16. Which one of the following statements regarding matter is not correc

Which one of the following statements regarding matter is *not* correct ?

Matter is anything that occupies space

At high temperatures matter becomes plasma

All matter is composed of large particles such as atoms and molecules

Colloids are made up of larger particles of matter

This question was previously asked in

UPSC CAPF – 2010

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The statement that is *not* correct regarding matter is “All matter is composed of large particles such as atoms and molecules”.

While atoms and molecules are fundamental building blocks for common states of matter (solid, liquid, gas), not *all* matter is composed *only* of atoms and molecules, especially described as “large particles”. Matter can exist as plasma (ionized gas, consisting of ions and free electrons), which is not composed of intact atoms or molecules. Fundamental particles (like quarks, electrons, neutrinos) are also considered matter. The term “large particles” is also relative and misleading in a fundamental description of matter composition. Statements A, B, and D are correct descriptions of aspects of matter: A) Matter occupies space and has mass. B) Plasma is a high-temperature state of matter. D) Colloids are indeed dispersions of particles larger than those in true solutions.

The four common states of matter are solid, liquid, gas, and plasma. Bose-Einstein condensates are another state of matter at extremely low temperatures. Matter is fundamentally composed of elementary particles, which can combine to form composite particles like protons and neutrons, which in turn form atomic nuclei. Atoms consist of a nucleus and electrons, and atoms combine to form molecules or ionic lattices.

17. Which one of the following is a compound ?

Which one of the following is a compound ?

Milk

Sugar

Tea

Coffee

This question was previously asked in

UPSC CAPF – 2010

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Among the given options, Sugar is a compound.

A compound is a substance formed when two or more different chemical elements are chemically bonded together in a fixed proportion. Milk, Tea, and Coffee are all mixtures. They consist of various substances physically mixed together, not chemically bonded in fixed ratios. “Sugar” typically refers to sucrose (C₁₂H₂₂O₁₁), which is a molecule composed of atoms of carbon, hydrogen, and oxygen chemically bonded in a fixed ratio, making it a compound.

A mixture is a substance consisting of two or more components not chemically combined. The components of a mixture retain their individual properties and can often be separated by physical means. Examples include air (mixture of gases), salt water (salt dissolved in water), milk, tea, and coffee.

18. Ice is lighter than pure water and floats on the surface. Which one of

Ice is lighter than pure water and floats on the surface. Which one of the following statements is correct to explain this phenomenon ?

The structure of ice is similar to that of water

Ice has a disordered 3-dimensional structure

Hydrogen-bonding in ice gives an open type structure with interstitial holes

There is no hydrogen bonding in water

This question was previously asked in

UPSC CAPF – 2010

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The correct statement explaining why ice is lighter than pure water is that hydrogen-bonding in ice gives an open type structure with interstitial holes.

In the solid state (ice), water molecules are held in a crystalline structure by hydrogen bonds. This structure is an open lattice containing hexagonal rings, with significant empty space or “interstitial holes” between the molecules. In the liquid state (water), although hydrogen bonds are still present and constantly breaking and reforming, the structure is less ordered and more compact than ice. As a result, a given mass of ice occupies a larger volume than the same mass of liquid water at the same temperature, leading to ice having a lower density and thus floating on water.

Most substances become denser in the solid state than in the liquid state. Water is unusual in this regard, exhibiting anomalous expansion (or contraction) upon melting or freezing. The density of water is maximum at 4°C. This property is crucial for aquatic life in cold climates, as ice forms on the surface, insulating the water below.

19. The vesting of ‘residuary’ powers in the central government by the Con

The vesting of ‘residuary’ powers in the central government by the Constitution of India indicates :

that India is a federal polity.

that India is neither federal nor unitary.

that India is quasi federal.

unitary character of Indian polity.

This question was previously asked in

UPSC CAPF – 2010

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The vesting of ‘residuary’ powers in the central government by the Constitution of India indicates the unitary character of Indian polity.

– In a federal system, powers are divided between the central government and state governments. Residuary powers are powers not enumerated in any list.
– Giving these unenumerated powers to the central government is a feature that strengthens the centre relative to the states.
– This centralizing tendency is a characteristic of a unitary bias or unitary features within a federal or quasi-federal structure.
– While India is often described as quasi-federal (option C), the *specific indication* of vesting residuary powers in the centre points towards the strength of the union government, which is a unitary characteristic. Purely federal systems might vest residuary powers with the states (like in the USA).

Article 248 of the Indian Constitution deals with Residuary Powers of Legislation. It states that Parliament has exclusive power to make any law with respect to any matter not enumerated in the Concurrent List or State List. This is a clear constitutional provision favoring the central government, highlighting a significant deviation from strict federalism and leaning towards a unitary structure in terms of legislative authority over residual subjects.

20. Gases may be distinguished from other forms of matter by their :

Gases may be distinguished from other forms of matter by their :

lack of colour.

ability to flow.

inability to form free surfaces.

ability to exert a buoyant force.

This question was previously asked in

UPSC CAPF – 2010

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Gases may be distinguished from other forms of matter by their inability to form free surfaces.

– Solids have fixed shape and volume. Liquids have fixed volume but take the shape of the container from the bottom up, forming a free surface under gravity. Gases take the shape and volume of the entire container.
– Gases expand to fill whatever container they are in, meaning they do not form a distinct boundary or “free surface” in the way liquids do.
– Lack of colour (A) is not universal for gases (e.g., NO2 is brown).
– Ability to flow (B) is characteristic of both liquids and gases (they are both fluids).
– Ability to exert a buoyant force (D) is also characteristic of both liquids and gases (both are fluids).

The defining characteristics of gases at a macroscopic level include: they have no fixed shape or volume, they are easily compressible, and they diffuse readily. The inability to form a free surface is a direct consequence of their molecules having high kinetic energy and weak intermolecular forces, causing them to spread out and occupy the entire volume of the container.