UPSC CAPF Archives

21. Which one of the following diseases is caused by Cadmium pollution?

Which one of the following diseases is caused by Cadmium pollution?

Minamata

Itai-itai

Fluorosis

Blue baby syndrome

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UPSC CAPF – 2017

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The correct answer is B) Itai-itai.

Itai-itai disease is a severe form of osteomalacia (softening of bones) associated with kidney dysfunction, caused by chronic exposure to cadmium poisoning. It was first reported in Japan, caused by cadmium released into rivers by mining activities.

A) Minamata disease is a neurological syndrome caused by severe mercury poisoning. It was first discovered in Minamata, Japan.
C) Fluorosis is a condition caused by excessive intake of fluoride, affecting bones and teeth.
D) Blue baby syndrome (Methemoglobinemia) is a condition in infants caused by nitrates in drinking water, which interferes with the blood’s ability to carry oxygen.

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22. Which of the following are the necessary conditions for the growth of

Which of the following are the necessary conditions for the growth of coral reefs?

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1. Photic conditions
2. Clean and sediment free water
3. Sea salinity of 6%
4. Tropical sea water with temperature of 20°C to 21°C

Select the correct answer using the code given below :

1, 2 and 4 only

2 and 4 only

1 and 3 only

1, 2, 3 and 4

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The correct answer is A) 1, 2 and 4 only.

Coral reefs are complex ecosystems built by tiny marine animals called coral polyps. Their growth depends on specific environmental conditions:
1. **Photic conditions:** Corals have a symbiotic relationship with photosynthetic algae called zooxanthellae living in their tissues. These algae require sunlight for photosynthesis, which provides energy to the coral. Therefore, coral reefs are typically found in shallow, clear waters within the photic zone.
2. **Clean and sediment free water:** Sediments suspended in water can block sunlight needed by zooxanthellae and can also smother coral polyps. Pollution can also harm corals. Clean water is essential.
3. **Sea salinity of 6%:** This is incorrect. Coral reefs typically require stable salinity levels found in normal seawater, which is usually around 30-40 parts per thousand (ppt), or 3-4%. A salinity of 6% (60 ppt) is significantly higher than optimal and is not conducive to coral growth.
4. **Tropical sea water with temperature of 20°C to 21°C:** Corals thrive in warm tropical and subtropical waters. The ideal temperature range for most reef-building corals is generally between 20°C and 28°C (68°F to 82°F). The range 20-21°C falls within this suitable range.

Other conditions necessary for coral reef growth include adequate water circulation to bring nutrients and remove waste, and a hard substrate for larvae to settle on. Coral bleaching, a major threat to reefs, occurs when corals expel their symbiotic algae, often due to increased water temperature.

23. Which one of the following statements about land tenure system is NOT

Which one of the following statements about land tenure system is NOT correct?

During the British rule in India three categories of land tenure system, viz. Zamindari, Mahalwari and Ryotwari were introduced

Under Zamindari system, land was held by one person or at the most by a few joint owners who were responsible for the payment of land revenue

Under the Mahalwari system, the agricultural lands belonged to the Government

Under Ryotwari system, the individual holders had the permanent rights over land and were directly responsible for payment of land revenue

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UPSC CAPF – 2017

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The correct answer is C) Under the Mahalwari system, the agricultural lands belonged to the Government.

This statement is incorrect. Under the Mahalwari system, the land revenue settlement was made with the village community (Mahal) as a whole or with the headman of the village on behalf of the community. The agricultural lands typically belonged to the villagers collectively or individually within the village, and the community was jointly responsible for the payment of revenue, although the government fixed the revenue for the entire Mahal. The land did not belong to the Government.

A) During the British rule, the three major land tenure systems were indeed Zamindari (or Permanent Settlement), Mahalwari, and Ryotwari.
B) Under the Zamindari system, the Zamindars were recognized as proprietors of the land and were responsible for collecting rent from the cultivators (ryots) and paying a fixed revenue to the British government.
D) Under the Ryotwari system, settlement was made directly with the individual cultivator (Ryot), who was recognized as the owner of the land and was directly responsible for the payment of land revenue to the government. This system gave Ryots permanent rights over land as long as they paid the revenue.

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24. In March 2017, a High Court in India had accorded the status of living

In March 2017, a High Court in India had accorded the status of living human entities to which two of the following rivers?

Brahmaputra and Ganga

Ganga and Yamuna

Yamuna and Godavari

Krishna and Kaveri

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UPSC CAPF – 2017

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The correct answer is B) Ganga and Yamuna.

In March 2017, the Uttarakhand High Court, in a landmark judgment, granted the status of living human entities (legal persons) to the Ganga and Yamuna rivers, including their tributaries. This ruling aimed to protect the rivers and recognize their ecological and cultural significance.

The judgment appointed individuals (like the Director of the Namami Gange project, the Chief Secretary of Uttarakhand, and the Advocate General of Uttarakhand) as legal custodians responsible for conserving and protecting the rivers. The ruling was inspired by a similar decision in New Zealand which granted legal personhood to the Whanganui River. However, this judgment was later stayed by the Supreme Court of India, which cited practical difficulties in implementing the decision.

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25. If all students are boys and all boys are dancers, then which one of t

If all students are boys and all boys are dancers, then which one of the following statements is definitely true?

All dancers are boys

All boys are students

All dancers are students

All students are dancers

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UPSC CAPF – 2017

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The given statements are:
1. All students are boys. (If someone is a student, then that person is a boy. Student -> Boy)
2. All boys are dancers. (If someone is a boy, then that person is a dancer. Boy -> Dancer)
We can combine these two conditional statements using the principle of transitivity:
If Student -> Boy and Boy -> Dancer, then it logically follows that Student -> Dancer.
This means, “If someone is a student, then that person is a dancer,” which can be rephrased as “All students are dancers.”
Let’s examine the options based on this deduction:
A) All dancers are boys (Dancer -> Boy). This is the converse of “All boys are dancers” and is not necessarily true.
B) All boys are students (Boy -> Student). This is the converse of “All students are boys” and is not necessarily true.
C) All dancers are students (Dancer -> Student). This is the converse of the derived conclusion “All students are dancers” and is not necessarily true.
D) All students are dancers (Student -> Dancer). This is the direct logical conclusion derived from the premises.

This problem requires understanding logical implication and how to chain conditional statements (syllogism). If P implies Q, and Q implies R, then P implies R.

Using Venn diagrams can also help visualize this. Draw a circle for ‘Students’ inside a circle for ‘Boys’. Then draw the ‘Boys’ circle inside a larger circle for ‘Dancers’. It becomes clear that the ‘Students’ circle is entirely contained within the ‘Dancers’ circle, meaning all students are dancers. The reverse relationships (e.g., all dancers are boys) are not guaranteed, as there can be dancers who are not boys (and thus not students).

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26. A 3 digit number 4X3 is added to 984 to get a 4 digit number 13Y7. If

A 3 digit number 4X3 is added to 984 to get a 4 digit number 13Y7. If 13Y7 is divisible by 11, then what is the value of (X+Y) ?

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UPSC CAPF – 2017

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The addition is 4X3 + 984 = 13Y7.
Let’s perform the addition column by column:
Units place: 3 + 4 = 7. This matches the unit digit of 13Y7. No carry-over to the tens place.
Tens place: X + 8 = Y (plus carry-over from units, which is 0). So, X + 8 = Y. Since Y is a single digit, X + 8 must be less than 10.
Hundreds place: 4 + 9 (plus carry-over from tens) = 13. The sum is 13Y7, which is a 4-digit number starting with 13. This means the sum in the hundreds place is indeed 13, and there was no carry-over from the tens place to the hundreds place.
So, X + 8 = Y, where Y is a digit between 0 and 9.
The possible values for X (a digit between 0 and 9) that result in a single digit Y are:
If X=0, Y = 0+8 = 8. The sum is 1387.
If X=1, Y = 1+8 = 9. The sum is 1397.
If X=2, Y = 2+8 = 10. Y cannot be 10 as it’s a single digit.
So, either X=0, Y=8 (sum=1387) or X=1, Y=9 (sum=1397).

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We are given that 13Y7 is divisible by 11.
Using the divisibility rule for 11: The alternating sum of the digits (starting from the right) must be divisible by 11.
For 13Y7: +7 – Y + 3 – 1 = 9 – Y.
For 13Y7 to be divisible by 11, 9 – Y must be a multiple of 11 (0, 11, -11, etc.).
Since Y is a digit (0-9), 9 – Y can range from 9-0=9 to 9-9=0.
The only multiple of 11 in this range is 0.
So, 9 – Y = 0, which means Y = 9.

Now we use the relation X + 8 = Y. Substitute Y=9:
X + 8 = 9
X = 9 – 8 = 1.
So, X=1 and Y=9.

Let’s verify: 413 + 984 = 1397.
Is 1397 divisible by 11? 7 – 9 + 3 – 1 = 0. Yes, it is.

The value requested is (X + Y).
X + Y = 1 + 9 = 10.

This problem combines basic arithmetic addition with the divisibility rule for 11 and digit constraints.

The divisibility rule for 11 states that a number is divisible by 11 if the difference between the sum of the digits at odd positions (from the right) and the sum of the digits at even positions (from the right) is divisible by 11 (i.e., 0, 11, -11, 22, etc.).

27. Which one of the following is the smallest number by which 2880 must b

Which one of the following is the smallest number by which 2880 must be divided in order to make it a perfect square ?

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Answer is Wrong!

This question was previously asked in

UPSC CAPF – 2017

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To find the smallest number by which 2880 must be divided to make it a perfect square, we first find the prime factorization of 2880.
2880 = 288 * 10 = (144 * 2) * (2 * 5) = (12² * 2) * (2 * 5) = ((2² * 3)²) * 2² * 5 = (2⁴ * 3²) * 2² * 5 = 2⁶ * 3² * 5¹
For a number to be a perfect square, the exponents of all its prime factors must be even. In the factorization 2⁶ * 3² * 5¹, the exponents are 6 (even), 2 (even), and 1 (odd).
To make the exponent of 5 even (which is 1), we must divide by 5 raised to the power of its odd exponent, i.e., 5¹.
So, we must divide 2880 by 5.
2880 / 5 = 576.
Let’s check if 576 is a perfect square: 576 = 24 * 24 = 24². Yes, it is.
Therefore, the smallest number by which 2880 must be divided is 5.

A number is a perfect square if and only if the exponents of all prime factors in its prime factorization are even. To make a number a perfect square by division, divide by the product of prime factors with odd exponents, each raised to the power of their odd exponent.

If the question asked for the smallest number to *multiply* by, you would multiply by the product of the prime factors with odd exponents, each raised to the power needed to make the exponent even (which is the odd exponent itself). In this case, multiply by 5¹.

28. The mass number of an element is NOT changed when it emits

The mass number of an element is NOT changed when it emits

Alpha and Beta radiations only

Alpha and Gamma radiations only

Beta and Gamma radiations only

Alpha, Beta and Gamma radiations

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The mass number (A) of an element is the total number of protons and neutrons in the nucleus.
– Alpha (α) decay: Emits a ⁴₂He nucleus. The mass number decreases by 4.
– Beta (β) decay (β⁻ or β⁺ or electron capture): In β⁻ decay, a neutron turns into a proton (A remains same, Z increases by 1). In β⁺ decay, a proton turns into a neutron (A remains same, Z decreases by 1). In electron capture, a proton captures an electron to become a neutron (A remains same, Z decreases by 1). In all Beta decay processes, the mass number does NOT change.
– Gamma (γ) decay: Emits a high-energy photon. This occurs when a nucleus transitions from a higher energy state to a lower energy state. Neither the atomic number (Z) nor the mass number (A) changes during gamma decay.
Therefore, the mass number is NOT changed when Beta and Gamma radiations are emitted.

Alpha decay changes both atomic number and mass number. Beta and Gamma decay do not change the mass number.

Radioactive decay processes result in the transformation of one atomic nucleus into another or into a lower energy state. The type of decay determines how the atomic number and mass number of the nucleus change.

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29. Who among the following has coined the term ‘Quark’, the fundamental p

Who among the following has coined the term ‘Quark’, the fundamental particles that make up protons and neutrons in an atomic nucleus ?

Richard Feynman

Murray Gell-Mann

Albert Einstein

Niels Bohr

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The term ‘Quark’ for the fundamental particles that make up protons and neutrons was coined by American physicist Murray Gell-Mann in 1964. He proposed the quark model independently of George Zweig, who had called the particles “aces”. Gell-Mann chose the name “quark” from James Joyce’s novel “Finnegans Wake”.

Murray Gell-Mann proposed the quark model and named these fundamental particles ‘quarks’.

Protons and neutrons are baryons, which are composed of three quarks. For example, a proton is made of two up quarks and one down quark (uud), and a neutron is made of one up quark and two down quarks (udd).

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30. Which one of the following is the chemical name of heavy water ?

Which one of the following is the chemical name of heavy water ?

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Hydrogen oxide

Deuterium dioxide

Deuterium oxide

Heavy hydrogen oxide

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Heavy water is a form of water in which the hydrogen atoms are replaced by deuterium, an isotope of hydrogen with one proton and one neutron (compared to normal hydrogen, protium, which has one proton and no neutrons). The chemical formula for heavy water is D₂O or ²H₂O. The standard chemical name for D₂O is Deuterium oxide.

Heavy water is water composed of deuterium and oxygen. Deuterium is an isotope of hydrogen.

Heavy water is used primarily as a moderator and coolant in certain types of nuclear reactors (specifically, Pressurized Heavy-Water Reactors like the CANDU reactor) because deuterium absorbs fewer neutrons than normal hydrogen.