UPSC CAPF Archives

11. At what time between 2 o’clock and 3 o’clock will the hour and minute

At what time between 2 o’clock and 3 o’clock will the hour and minute hands of a clock be 12 minutes division apart?

12 minutes past 2 o'clock

18 minutes past 2 o'clock

24 minutes past 2 o'clock

30 minutes past 2 o'clock

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The correct answer is C) 24 minutes past 2 o’clock.

At 2 o’clock, the hour hand is at the ‘2’ mark and the minute hand is at the ’12’ mark. The distance between them is 10 minute divisions (each minute mark represents 1 minute or 6 degrees; 5 minute divisions between 12 and 1, 1 and 2, so 10 divisions). We want the hands to be 12 minute divisions (12 * 6 = 72 degrees) apart.
The minute hand moves 6 degrees per minute. The hour hand moves 0.5 degrees per minute. The relative speed of the minute hand with respect to the hour hand is 5.5 degrees per minute.
At 2:00, the hour hand is at 60 degrees from 12 (2 * 30), and the minute hand is at 0 degrees. The hour hand is 60 degrees ahead of the minute hand.
We want the difference in angles to be 72 degrees. This can be when the minute hand is 72 degrees behind the hour hand, or 72 degrees ahead.
Let ‘t’ be the time in minutes past 2.
Angle of minute hand = 6t.
Angle of hour hand = 60 + 0.5t.
We want |6t – (60 + 0.5t)| = 72.
|5.5t – 60| = 72.
Case 1: 5.5t – 60 = 72 => 5.5t = 132 => t = 132 / 5.5 = 1320 / 55 = 24.
Case 2: 5.5t – 60 = -72 => 5.5t = -12 => t = -12 / 5.5, which is not possible for time after 2:00.
So, the time is 24 minutes past 2 o’clock. At 2:24, the minute hand is at 24 * 6 = 144 degrees. The hour hand is at 60 + 24 * 0.5 = 60 + 12 = 72 degrees. The difference is 144 – 72 = 72 degrees, which is 12 minute divisions (72/6).

The relative speed of the minute hand w.r.t. hour hand is 5.5 degrees per minute, or 11/12 minute divisions per minute. At 2 o’clock, the hour hand is 10 minute divisions ahead of the minute hand. To be 12 divisions apart, the minute hand must gain (10 + 12) = 22 divisions if it’s ahead, or gain (10 – (-12)) = 22 if behind (but this means passing the hour hand, which happens at 2:24 anyway). The minute hand needs to gain 22 minute divisions relative to the hour hand from the 12 o’clock position where both hypothetically start together. The hour hand is effectively at 10 minute divisions at 2:00. The minute hand starts at 0. The relative gain required is the initial gap plus the desired gap. Initial gap is 10 min divisions. Desired gap is 12 min divisions. Total gain required = 10 + 12 = 22 minute divisions (for the minute hand to be ahead). Time = Gain / Relative speed = 22 / (11/12) = 22 * (12/11) = 2 * 12 = 24 minutes.

12. Arabian Sea records higher salinity than the Bay of Bengal because

Arabian Sea records higher salinity than the Bay of Bengal because

Arabian Sea exhibits high rate of evaporation and low influx of fresh-water

Arabian Sea has shallow water

Arabian Sea has more enclosed land

Arabian Sea receives more rainfall

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The correct answer is A) Arabian Sea exhibits high rate of evaporation and low influx of fresh-water.

Salinity in oceans is primarily affected by evaporation, precipitation, freshwater influx from rivers, and freezing/melting of ice. The Arabian Sea experiences a higher rate of evaporation due to clearer skies and higher temperatures in parts influenced by dry winds. Crucially, the Bay of Bengal receives enormous volumes of freshwater from large rivers like the Ganga, Brahmaputra, Mahanadi, Godavari, Krishna, and Cauvery, which significantly dilutes its water and lowers its salinity compared to the Arabian Sea, which receives fewer major rivers.

Average salinity of the Arabian Sea is around 36 parts per thousand (ppt), while the average salinity of the Bay of Bengal is lower, around 30-33 ppt, particularly lower near the river mouths.

13. Which one of the following major river basins of India is the shortest

Which one of the following major river basins of India is the shortest in length and smallest in terms of catchment area?

Cauvery

Mahi

Penner

Sabarmati

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The correct answer is D) Sabarmati.

Comparing the approximate lengths and catchment areas of the given major river basins:
– Cauvery: Length ~800 km, Catchment Area ~81,155 sq km
– Mahi: Length ~583 km, Catchment Area ~34,842 sq km
– Penner: Length ~597 km, Catchment Area ~55,213 sq km
– Sabarmati: Length ~371 km, Catchment Area ~21,674 sq km
Sabarmati is the shortest in length and has the smallest catchment area among these four rivers.

The Sabarmati is one of the major west-flowing rivers of India. It originates in the Aravalli Range of Rajasthan and flows through Rajasthan and Gujarat into the Arabian Sea.

14. Which one of the following is in descending order of Indian States in

Which one of the following is in descending order of Indian States in terms of their density of population (as per 2011 Census)?

Bihar—Kerala—Uttar Pradesh—West Bengal

West Bengal—Bihar—Kerala—Uttar Pradesh

Bihar—West Bengal—Kerala—Uttar Pradesh

Kerala—West Bengal—Bihar—Uttar Pradesh

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The correct answer is C) Bihar—West Bengal—Kerala—Uttar Pradesh.

According to the 2011 Census of India, the population densities of the mentioned states are:
– Bihar: 1106 persons per sq km
– West Bengal: 1028 persons per sq km
– Kerala: 860 persons per sq km
– Uttar Pradesh: 829 persons per sq km
Arranging these in descending order of population density gives: Bihar > West Bengal > Kerala > Uttar Pradesh.

Population density is calculated as the number of people per unit area (usually square kilometer). Bihar has the highest population density among all Indian states. The national average density according to the 2011 census was 382 persons per sq km.

15. Which of the following cities experience the warm temperate Mediterran

Which of the following cities experience the warm temperate Mediterranean climate?

1. Cape Town
2. Los Angeles
3. Adelaide
4. Santiago

Select the correct answer using the code given below.

1 and 2 only

3 and 4 only

1, 2 and 3 only

1, 2, 3 and 4

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The correct answer is D) 1, 2, 3 and 4.

The warm temperate Mediterranean climate is typically found on the western margins of continents between 30° and 45° latitudes in both hemispheres. It is characterized by hot, dry summers and mild, wet winters. All four listed cities are located in regions that experience this type of climate.

Cape Town (South Africa, ~34°S), Los Angeles (USA, ~34°N), Adelaide (Australia, ~35°S), and Santiago (Chile, ~33°S) are classic examples of cities with Mediterranean climates. These regions benefit from subtropical high-pressure systems during summer, leading to dry conditions, and are influenced by westerlies and frontal systems during winter, bringing precipitation.

16. Match List-I with List-II and select the correct answer using the code

Match List-I with List-II and select the correct answer using the code given below the Lists :

List-I (Limestone region)	List-II (Country)
A. Pennines	1. France
B. Yucatan Peninsula	2. Jamaica
C. Cockpit Country	3. Britain
D. Causses	4. Mexico

A-3, B-4, C-2, D-1

A-1, B-2, C-4, D-3

A-3, B-2, C-4, D-1

A-1, B-4, C-2, D-3

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This question asks to match well-known limestone (karst) regions with the countries where they are located.
A. Pennines is a range of hills often called the “backbone of England”. England is part of Great Britain, hence Pennines is in Britain. Matches with 3.
B. The Yucatan Peninsula is a large landmass in southeastern Mexico, also extending into Belize and Guatemala. Mexico is the principal country associated with it in a geographical context. Matches with 4.
C. Cockpit Country is a rugged, hilly region of central Jamaica known for its distinctive karst topography featuring conical hills and sinkholes. Matches with 2.
D. The Causses are a series of limestone plateaus in the Massif Central region of France, characterized by deep canyons and karst features. Matches with 1.
Therefore, the correct matching is A-3, B-4, C-2, D-1.

This question tests knowledge of specific geographic locations famous for their karst geomorphology and the countries where they are found.

Karst topography develops in regions underlain by soluble rocks like limestone, dolomite, or gypsum, characterized by sinkholes, caves, and underground drainage systems. Famous karst regions exist worldwide, reflecting the widespread distribution of carbonate rocks.

17. Which one of the following statements regarding insulin hormone is

Which one of the following statements regarding insulin hormone is correct?

Insulin is a protein hormone which is not produced in human body.

Insulin is a steroid hormone which is produced in human body.

Insulin is a cholesterol-driven hormone given to human.

Insulin is a protein hormone which is produced in human body.

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Insulin is a hormone produced by the beta cells of the islets of Langerhans in the pancreas. It is crucial for regulating blood glucose levels by promoting glucose uptake and storage in various tissues. Chemically, insulin is classified as a peptide hormone (a type of protein hormone), composed of amino acids. It is not a steroid hormone, which are derived from cholesterol. Insulin is naturally produced in a healthy human body. People with type 1 diabetes, whose beta cells are destroyed, require exogenous insulin administration, but this does not mean it is not produced in the human body under normal circumstances.
Let’s evaluate the options:
A) Insulin is a protein hormone which is not produced in human body. Incorrect, it is produced in the human body.
B) Insulin is a steroid hormone which is produced in human body. Incorrect, it is produced but is a protein hormone.
C) Insulin is a cholesterol-driven hormone given to human. Incorrect, it is a protein hormone, not cholesterol-driven, though it is given to treat diabetes.
D) Insulin is a protein hormone which is produced in human body. Correct.

Insulin is a protein hormone produced by the pancreas in the human body, primarily involved in regulating blood glucose levels.

Other important hormones involved in glucose regulation include glucagon (also produced by the pancreas), which has opposite effects to insulin, raising blood glucose levels. Insulin and glucagon work together to maintain glucose homeostasis.

18. Which one of the following statements is correct?

Which one of the following statements is correct?

In photosynthesis by green plants, carbon dioxide is used for making carbohydrate.

During photosynthesis, plants use oxygen for making carbohydrate.

The carbohydrate generated by plants comes from soil.

The carbohydrate generated by plants comes from urea.

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Photosynthesis is the process by which green plants convert light energy into chemical energy in the form of organic compounds (carbohydrates). The inputs for photosynthesis are carbon dioxide (CO₂) and water (H₂O), and the outputs are glucose (a carbohydrate, C₆H₁₂O₆) and oxygen (O₂). The overall chemical equation is approximately 6CO₂ + 6H₂O + Light Energy → C₆H₁₂O₆ + 6O₂. This equation shows that carbon dioxide is directly incorporated into the carbohydrate molecule. Plants absorb CO₂ from the atmosphere through their stomata.
Let’s evaluate the other options:
B) Oxygen is produced as a byproduct during photosynthesis, not used to make carbohydrate.
C) While water and minerals essential for plant growth come from the soil, the carbon atoms that form the backbone of the carbohydrate molecule come from atmospheric carbon dioxide.
D) Urea is a nitrogenous compound used as a fertilizer to provide nitrogen for plant growth. Nitrogen is essential for synthesizing proteins and nucleic acids, but the carbon backbone of carbohydrates comes from CO₂.
Therefore, the correct statement is that carbon dioxide is used for making carbohydrate in photosynthesis.

In photosynthesis, plants use carbon dioxide and water, with the help of light energy and chlorophyll, to synthesize carbohydrates and release oxygen. Carbon dioxide is the source of carbon atoms in the carbohydrate.

Photosynthesis occurs in two main stages: the light-dependent reactions (where light energy is converted into chemical energy in the form of ATP and NADPH, and water is split) and the light-independent reactions (Calvin cycle), where the chemical energy is used to fix carbon dioxide and synthesize glucose.

19. Which one of the following statements regarding digestion is correct?

Which one of the following statements regarding digestion is correct?

Fat present in the food is digested by trypsin and chymotrypsin.

Starch of food is digested by lipases.

Fat of food is digested by lipases.

Nucleic acid is digested by amylases.

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Digestion involves enzymatic breakdown of macromolecules in food. Different types of enzymes are specific for different types of molecules. Fats (lipids, primarily triglycerides) are digested by enzymes called lipases. For example, pancreatic lipase is the main enzyme responsible for fat digestion in the small intestine, breaking triglycerides down into fatty acids and glycerol.
Let’s examine the other options:
A) Trypsin and chymotrypsin are proteases, enzymes that digest proteins into smaller peptides and amino acids. They do not digest fats.
B) Starch is a complex carbohydrate. Carbohydrates like starch are digested by amylases (e.g., salivary amylase, pancreatic amylase) into smaller sugars. Lipases digest fats.
D) Nucleic acids (DNA and RNA) are digested by nucleases into nucleotides. Amylases digest carbohydrates.
Thus, the correct statement is that fat of food is digested by lipases.

Specific enzymes are required to digest different classes of macromolecules: Lipases for fats, Amylases for carbohydrates (like starch), Proteases for proteins, and Nucleases for nucleic acids.

Bile salts, produced by the liver and stored in the gallbladder, are also important for fat digestion. They emulsify large fat globules into smaller droplets, increasing the surface area available for lipases to act upon.

20. Which one of the following statements regarding muscle contraction and

Which one of the following statements regarding muscle contraction and relaxation is correct?

It involves movement of Zn++ ion.

It involves Ca++ ion of blood.

It involves release of Ca++ from sarcoplasmic reticulum (SR) and pumping Ca++ back in SR.

It involves exchange of Na and K.

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Muscle contraction is initiated by a signal (usually from a motor neuron) that leads to a sequence of events culminating in the sliding of actin and myosin filaments. A critical step in this process is the increase in the concentration of calcium ions (Ca++) in the sarcoplasm (the cytoplasm of a muscle cell). This Ca++ is primarily stored in the sarcoplasmic reticulum (SR), a specialized endoplasmic reticulum in muscle cells. Upon receiving the signal, Ca++ is released from the SR into the sarcoplasm. These released Ca++ ions bind to regulatory proteins on the actin filaments, allowing myosin heads to bind and cause contraction. Muscle relaxation occurs when the signal stops. Ca++ ions are then actively transported back into the SR by Ca++ pumps (SERCA pumps) located on the SR membrane. The reduction in sarcoplasmic Ca++ concentration causes the regulatory proteins to block myosin binding sites again, leading to muscle relaxation. Therefore, the release of Ca++ from the SR and its subsequent pumping back into the SR are central events in muscle contraction and relaxation.

Muscle contraction and relaxation are directly regulated by the concentration of Ca++ ions in the sarcoplasm, which is controlled by the release and re-uptake of Ca++ by the sarcoplasmic reticulum.

While other ions like Na+ and K+ are crucial for the electrical signaling (action potential) that triggers muscle contraction, and Zn++ is involved in various metabolic processes, the direct mechanism governing the binding and unbinding of myosin to actin, which constitutes the contraction/relaxation cycle, is primarily regulated by the availability of intracellular Ca++.