[Answers with Explanation] UPSC prelims GS1 paper 2021

Q71. Water can dissolve more substances than any other liquid because:

(a) it is dipolar in nature
(b) it is a good conductor of heat
(c) it has a high value of specific heat
(d) it is an oxide of hydrogen

Solution A

Water is dipolar in nature: This is true. Water molecules have a bent shape, and the oxygen atom has a slightly negative charge while the hydrogen atoms have slightly positive charges. This polarity allows water molecules to form hydrogen bonds with other polar molecules, making it an excellent solvent for many substances.

Water is a relatively good conductor of heat compared to gases but not as good as metals. The presence of hydrogen bonds between water molecules slows down heat conduction compared to pure metals.

Q72. With reference to street lighting, how do sodium lamps differ from LED lamps?

1. Sodium lamps produce light in 360 degrees but it is not so in the case of LED lamps.
2. As street-lights, sodium lamps have a longer lifespan than LED lamps.
3. The spectrum of visible light from sodium lamps is almost monochromatic while LED lamps offer significant color advantages in street lighting.

Select the correct answer using the code given below.

(a) 3 only
(b) 2 only
(c) 1 and 3 only
(d) 1, 2 and 3

Solution C

Statement 1 is correct: Sodium lamps are omnidirectional, meaning they emit light in all directions, including upwards and downwards. In contrast, LED lamps are more directional, which allows them to focus light more efficiently in the desired direction, reducing light pollution.

Statement 2 is incorrect: Generally, LED lamps have a longer lifespan compared to sodium lamps. LED lamps can last significantly longer, often up to 2-4 times longer, than sodium lamps. This longer lifespan is one of the reasons why LED street lights have become more popular in recent years.

Statement 3 is correct: Sodium lamps primarily emit light in a narrow spectrum, resulting in a yellowish-orange glow. This limited color spectrum can make it challenging to distinguish colors accurately under sodium lighting. On the other hand, LED lamps offer a wider range of color temperatures, allowing for better color rendering and improved visibility at night.

Q73. The term ‘ACE2’ is talked about in the context of:

(a) genes introduced in the genetically modified plants
(b) development of India’s own satellite navigation system
(c) radio collars for wildlife tracking
(d) spread of viral diseases

Solution D

ACE2, which stands for Angiotensin-Converting Enzyme 2, is a protein found in the human body, particularly on the surface of cells in the lungs, heart, and blood vessels. It plays a vital role in the renin-angiotensin-aldosterone system (RAAS) and serves as the receptor for the SARS-CoV-2 virus responsible for causing COVID-19.

Option (d) Spread of viral diseases is correct: ACE2 gained significant attention during the COVID-19 pandemic because it serves as the receptor that allows the SARS-CoV-2 virus to enter human cells, leading to the spread of the viral infection.

Q74. Bisphenol A (BPA), a cause of concern, is a structural/key component in the manufacture of which of the following kinds of plastics?

(a) Low-density polyethylene
(b) Polycarbonate
(c) Polyethylene terephthalate
(d) Polyvinyl chloride

Solution B

Option (b) Polycarbonate is correct: BPA is a key component in the manufacture of polycarbonate plastics. Polycarbonate is a type of hard, transparent plastic commonly used in items like water bottles, eyewear lenses, and CDs/DVDs.

Q75. ‘Triclosan’, considered harmful when exposed to high levels for a long time, is most likely present in which of the following?

(a) Food preservatives
(b) Fruit-ripening substances
(c) Reused plastic containers
(d) Toiletries

Solution D

Triclosan is a chemical compound that has been widely used as an antibacterial agent in various products.
Triclosan has been commonly used in toiletries, such as soaps, toothpaste, and hand sanitizers, as an antibacterial agent. However, due to concerns about its potential health and environmental impact, its use has been restricted or phased out in many personal care products. However, India lacks any such regulation so far on the use of triclosan-based products.

Q76. Which one of the following is a reason why astronomical distances are measured in light-years?

(a) Distances among stellar bodies do not change.
(b) Gravity of stellar bodies does not change.
(c) Light always travels in a straight line.
(d) Speed of light is always the same.

Solution D

A light-year is a unit of astronomical distance, defined as the distance that light travels in one year in a vacuum. The reason astronomical distances are measured in light-years is because the speed of light in a vacuum is constant and does not change. In the theory of special relativity, the speed of light (denoted by “c”) is considered to be an absolute constant, approximately 299,792,458 meters per second (or about 186,282 miles per second).

Since light travels at a fixed speed, using light-years as a unit of distance allows astronomers to express vast distances accurately and consistently. Astronomical objects and events are often extremely far from Earth, and traditional units like kilometers or miles would be impractical for such vast distances. Light-years provide a more suitable scale for measuring these immense spans.

Q77. We adopted parliamentary democracy based on the British model, but how does our model differ from that model?

1. As regards legislation, the British Parliament is supreme or sovereign, but in India, the power of the Parliament to legislate is limited.
2. In India, matters related to the constitutionality of the Amendment of an Act of the Parliament are referred to the Constitution Bench by the Supreme Court.

Select the correct answer using the code given below.

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

Solution C

Statement 1 is correct: In the British model, the Parliament is considered supreme or sovereign, which means it has the authority to make or change any law without any legal limitations. However, in India, the power of the Parliament to legislate is limited by the Constitution. The Indian Parliament operates under a written constitution, and its legislative powers are subject to the provisions and limitations specified in the Constitution.

Statement 2 is correct: In India, if there is a question related to the constitutionality of an Amendment of an Act of the Parliament, the matter is referred to the Constitution Bench of the Supreme Court for interpretation and judgment. The Constitution Bench is a special bench of the Supreme Court consisting of five or more judges, and it deals with significant constitutional questions and matters of public importance.

The provision for a Constitution bench has been provided in the Constitution of India under Article 143 and Article 145(3). It is the Chief Justice of India who is constitutionally authorized to constitute a constitution bench and refer cases to it.

Q78. With reference to the Union Government, consider the following statements:

1. N. Gopalaswamy Iyenger Committee suggested that a minister and a secretary be designated solely for pursuing the subject of administrative reform and promoting it.
2. In 1970, the Department of Personnel was constituted on the recommendation of the Administrative Reforms Commission, 1966, and this was placed under the Prime Minister’s charge.

Which of the statements given above is/are correct?

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

Solution B

Statement 1 is incorrect: The N. Gopalaswamy Iyengar Committee did not recommend the designation of a minister and a secretary solely for pursuing administrative reform. The committee, appointed in 1959, made recommendations related to center-state relations and financial matters, but it did not suggest creating a dedicated minister and secretary for administrative reform.

Statement 2 is correct: The Department of Personnel was indeed constituted in 1970 on the recommendation of the Administrative Reforms Commission, 1966. The Administrative Reforms Commission, headed by Morarji Desai, had recommended the creation of this department to improve the functioning of the civil services and related administrative matters. It was initially placed under the charge of the Prime Minister.

Q79. ‘Right to Privacy’ is protected under which Article of the Constitution of India?

(a) Article 15
(b) Article 19
(c) Article 21
(d) Article 29

Solution C

In K. S. Puttaswamy Case (2017), the Supreme Court of India has held that the right to privacy is a Fundamental Right and it is protected under Article 21 of the Constitution of India. The Court reasoned that privacy is an incident of fundamental freedom or liberty guaranteed under Article 21. The Court also overruled M.P. Sharma and Kharak Singh judgments, in so far as the latter did not expressly recognize the right to privacy.

Q80. Consider the following statements:

1. In India, there is no law restricting the candidates from contesting in one Lok Sabha election from three constituencies.
2. In the 1991 Lok Sabha Election, Shri Devi Lal contested from three Lok Sabha constituencies.
3. As per the existing rules, if a candidate contests in one Lok Sabha election from many constituencies, his/her party should bear the cost of bye-elections to the constituencies vacated by him/her in the event of him/her winning in all the constituencies.

Which of the statements given above is/are correct?

(a) 1 only
(b) 2 only
(c) 1 and 3
(d) 2 and 3

(The Question was dropped by UPSC)

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