Daily Prelims Notes 28 May 2024

Daily Prelims Notes

28 May 2024

1. What are colours and how do people understand them?

Sub: Science and tech

Sec: Msc

What is colour?

• Colour is a type of information our eyes receive and process based on electromagnetic radiation. 
• An object by itself can’t be said to have a color  but based on which frequencies of visible-light radiation it absorbs, reflects, and/or scatters, we can perceive the object to have a particular color.

How are humans able to perceive colors?

• In the human eye, the rod and the cone cells receive information in the light that strikes the eye.
• The rod cells record brightness while the cone cells record the wavelengths, which the human brain interprets as color. 
• Human beings have three types of cone cells.
• Each type is sensitive to light of a different wavelength, and they work together to input color information to the brain.
• The possession of three types of cone cells is why humans are called trichromats.
• Many birds and reptiles, on the other hand, are tetrachromats (four types of cone cells).
• While human vision is restricted to wavelengths from 400 nm to 700 nm (visible light), honeybees can also ‘see’ ultraviolet light and mosquitoes and some beetles can access information in some wavelengths of infrared radiation

Science of colors:

• Until the late 19th century, traditional color theory specified the different ways in which dyes, pigments, and inks could be mixed to make other colors.
• In this paradigm, there were three primary colors e.g. red, yellow, and blue.
•  These colors when combined in different ways could produce all the colors the human eye is capable of seeing.
• Modern color theory, more accurately color science, rejected the idea of there being three fixed colors. According to color science, all the colors that could be produced by combining any three colors in different ways is called the gamut of those three colors.
• Each color in a gamut populates a given color space, and all color spaces are smaller than the full range of colors the eye can see.

Rendering of colors:

• There are two broad ways to render colors i.e. additive and subtractive coloring.
• In additive coloring, light of different wavelengths is ‘mixed’ to yield light of one combined color.
• A common color space associated with additive coloring is the RGB space: where red, green, and blue when added to each other in varying measures produces other colors.
• In subtractive coloring, a color is rendered by passing white light through a medium that absorbs, or takes away, specific wavelengths of light thereby leaving the rest to render a particular color.
• The typical examples include dyes, pigments, and inks. A dye is a chemical compound that can absorb certain wavelengths of light.
• When a cloth is dyed, the dying compound forms chemical bonds with compounds in the cloth and imbues the cloth with the corresponding color.

What are the properties of color?

• In color science, all colors however rendered are said to have a few appearance parameters: hue, brightness, lightness, and chromaticity.
• Hue:
  • A Technical committee of the International Commission on Illumination specified the definition of hue to be the degree to which a given (perceived) color can be said to be “similar to or different from” perceived “red, orange, yellow, green, blue, violet”. 
  • Isaac Newton defined complementary colors on the basis of hue i.e. if two colors combine to produce a grayscale color  i.e. lacking in hue — they are complementary.
• Brightness:
  • Brightness is related to an object’s luminance. 
  • The luminance is the power emitted by a source of light per unit area, weighted by wavelength.
  • The eye’s subjective perception of this power in some direction is inferred as the source’s brightness.
• Lightness:
  • Lightness refers to the extent to which a coloured object appears light compared to a white-coloured object that is well lit.
• Chromaticity:
  • The chromaticity, or chromatic intensity, has to do with the human perception of color and depends on the color’s quality irrespective how well it is lit.

What are LEDs?

• A light-emitting diode (LED) is a semiconductor device that emits light when an electric current is passed through it.
• Light is produced when the particles that carry the current (known as electrons and holes) combine together within the semiconductor material.

What are Blue LEDs?

• Blue LED Light can be defined as light given off from light-emitting diodes (LEDs) in the visible light spectrum between the wavelengths of 400 to 500 nanometers (nm). 
• Blue Light sits on the spectrum between violet and green.
• Blue LEDs have an active region consisting of one or more InGaN quantum wells sandwiched between thicker layers of GaN, called cladding layers.
• By varying the relative In/Ga fraction in the InGaN quantum wells, the light emission can in theory be varied from violet to amber.

2. Why has NASA launched a tiny satellite to measure heat lost from Earth’s poles?

Sub: Science and tech

Sec: Space sector

Context:

• On May 25, the National Aeronautics and Space Administration (NASA) launched one of the two climate satellites, which would study heat emissions at Earth’s poles, sitting atop Rocket Lab’s Electron rocket from Mahia in New Zealand.

More on news:

• The second satellite will be launched in the following days.
• The two shoebox-sized cube satellites or CubeSats will measure how much heat the Arctic and Antarctica, i.e. two of the coldest regions on the Earth,  radiate into space and how this influences the planet’s climate.
• The mission has been named PREFIRE (Polar Radiant Energy in the Far-InfraRed Experiment) and was jointly developed by NASA and the University of Wisconsin-Madison (US).

What are CubeSats?

• CubeSats are essentially miniature satellites whose basic design is a 10 cm x 10 cm x 10 cm (which makes up for “one unit” or “1U”) cube, just a little bigger than a Rubik’s cube  and weight not more than 1.33 kg.
• Depending on the CubeSat’s mission, the number of units can be 1.5, 2, 3, 6, and 12U, according to NASA.
• These satellites were first developed in 1999 by California Polytechnic State University at San Luis Obispo and Stanford University as educational tools.
• Owing to their low cost and less mass in comparison to traditional satellites, they began to be put in orbit for technology demonstrations, scientific research, and commercial purposes.
• Each of the PREFIRE satellites is a 6U CubeSat.
• They measure around 90 cm in height and nearly 120 cm in width when the solar panels, which will power the satellite, are deployed.
• The two satellites will be placed in a near-polar orbit at an altitude of about 525 kilometers.

Why do researchers want to measure heat emissions at Earth’s poles?

• It has to do with the Earth’s energy budget, which is the balance between the amount of heat incoming to Earth from the Sun and the amount of heat outgoing from Earth into space. 
• The difference between the two determines the planet’s temperature and climate.
• A large amount of the heat radiated from the Arctic and Antarctica is emitted as far-infrared radiation  wavelengths of 3 μm to 1,000 μm within the infrared range of electromagnetic radiation.

What is the PREFIRE mission?

• A mission designed for a pair of tiny satellites to measure a little-studied portion of the radiant energy emitted by Earth, for clues about sea ice loss, ice-sheet melting, and a warming Arctic.
• Its two CubeSats can study far-infrared radiation from the Earth’s pole and the data collected by them would help scientists better understand the energy budget of the planet.
• The observations will help us understand the fundamentals of Earth’s heat balance, allowing us to better predict how our ice, seas, and weather will change in the face of global warming.
• Each of the PREFIRE CubeSat is equipped with a thermal infrared spectrometer known as Thermal Infrared Spectrometer (TIRS) and is aimed to measure the amount of infrared and far-infrared radiation from the Arctic and Antarctica.
• The spectrometer features specially shaped-mirrors and detectors for splitting and measuring infrared light, according to NASA.
• The CubeSats will also measure the amount of far-infrared radiation trapped by atmospheric water vapor and clouds at the poles and how this influences the greenhouse effect in the region.

What are Small Satellites?

• A small satellite, miniaturized satellite, or smallsat is a satellite of low mass and size, usually under 1,200 kg.
• While all such satellites can be referred to as “small”, different classifications are used to categorize them based on mass.

3. Nothing ‘corrupt’ if promises in manifesto work out eventually for public’s financial benefit: SC

Sub: Polity

Sec: Elections

Tag: manifesto

Context:

• The Supreme Court of India has clarified that promises of financial assistance made by political parties in their election manifestos do not constitute a ‘corrupt practice’.

More on news:

• Mr. Sreedharan had challenged the election win of B.Z. Zameer Ahmed Khan, a Congress candidate, in the State Assembly election of 2023.

Key highlights of the case:

• The petitioner had challenged the election win of B.Z. Zameer Ahmed Khan, a Congress candidate, in the Karnataka Assembly election of 2023.
• The bench, comprising Justices Surya Kant and K V Viswanathan, stated that the contention that such promises could be seen as corrupt was too far fetched.
• The contention of the counsel that the commitments by a political party in its manifesto, which eventually lead to direct or indirect financial help to the public at large, will also amount to corrupt practice by a candidate of that party, is too far-fetched and cannot be accepted.
• The court emphasized that commitments leading to direct or indirect financial benefits for the public, as outlined in party manifestos, are legally permissible under election laws.
• This ruling sets a significant precedent in how election promises are interpreted legally in India.

What is the election manifesto?

• A manifesto is generally defined as a published declaration of the intentions, motives or views of an individual, group, political party or government whosoever issues it. 
• A manifesto usually comprises a previously published opinion or public consensus and/or promotes a new idea with prescriptive notions for carrying out changes for future.
• An election manifesto is a published document containing declaration of the ideology, intentions, views, policies and programmes of a political party. 
• The Election Manifestos are generally drafted by the Political Parties keeping an eye on forthcoming elections and are generally published and well publicized.

What are freebies?

• Freebies that are usually distributed include goods like bicycles, smart phones, TVs, Laptops and waivers on bills (water, electricity, etc.).
• Freebies and poll promises are different from subsidies which are required for the proper functioning of a government to fulfill peoples’ needs and may not be a part of government poll promises.

Supreme Court views on FreeBies:

• The Supreme Court in S Subramaniam Balaji vs Government of Tamil Nadu 2013 case held that unrealistic poll promises and freebies are a serious issue that disturbs the level-playing field in elections.
• In the Balaji case judgment, a Division Bench of the Supreme Court had held that making promises in election manifestos do not amount to a ‘corrupt practice’ under Section 123 of the Representation of People Act (RP).

4. More than 2000 buried in Papua New Guinea landslip

Sub: IR

Sec: Places in news

Tag: Papua New Guinea landslip’

Context:

• A deadly landslide which villagers in Papua New Guinea say struck like “an exploding bomb” may have buried more than 2,000 people alive.

Details:

• Landslip at Kaokalam village, Yambali in Enga Province of Papua New Guinea.
• The Mount Mungalo landslide occurred in the highlands of Enga, in the north of the island nation.
• Reason for the landslide: Local officials and reporters have attributed the mountain’s collapse to weeks of heavy rain and other wet conditions in the area.
• The ground is quite unstable at the moment and it is at risk of triggering further landslide.

About Papua New Guinea:

• Location: It is an island country that lies in the south-western Pacific.
• It includes the eastern half of New Guinea (the world’s second-largest island) and many small offshore islands.
• Neighbours: Indonesia to the west, Australia to the south, and the Solomon Islands to the southeast.
• Capital: Port Moresby
• Terrain: It is mainly mountainous but has low-lying plains in southern New Guinea.
• The islands that constitute Papua New Guinea were settled over a period of 40,000 years by a mixture of peoples who are generally referred to as Melanesians.
• Language:
  • English is the main language of government and commerce. In most everyday contexts, the most widely spoken language is Tok Pisin. 
  • Linguistically, it is the world’s most diverse country, with more than 800 languages.
• Religion: The majority of Papua New Guinea’s people are at least nominally Christian.
• Government:
  • Papua New Guinea became self-governing on December 1, 1973, and achieved independence on September 16, 1975.
  • The country is a constitutional monarchy and a member of the Commonwealth.
  • The British monarch (At present ‘King Charles III’), represented by a governor-general, is the head of state, and the Prime Minister is the head of government.

Source: TH

5. The controversy over eucalyptus planting in Kerala

Sub: Environment

Sec: Species in news

Tag: eucalyptus

Context:

• The Kerala government allowed the Kerala Forest Development Corporation (KFDC) to plant eucalyptus trees for financial reasons in 2024-2025.
• Environmentalists protested, citing potential adverse effects on forests and increased human-animal conflicts.
• The head of the Forest Force clarified that planting eucalyptus inside forests was not permitted.
• On May 20, the government revised the order to limit the cutting of exotic tree species only to KFDC-controlled lands.
• The government’s revised order and eco-restoration efforts aim to align forestry practices with ecological and environmental sustainability goals.

About KFDC and Its Plantations:

• Establishment: January 24, 1975.
• The area under KDFC: Approximately 7,000 hectares of plantations.
• Species: Includes Eucalyptus grandis, Acacia auriculiformis, Acacia mangium, Acacia crassicarpa, Acacia pycnantha (also known as wattle), Alnus nepalensis, Casuarina equisetifolia, and Pinus patula.
• Rotation Ages of these species: Eucalyptus (9 years), Acacia auriculiformis (18 years), Acacia mangium (7 years).
• At the end of each cycle, plantations approved by the Union Ministry of Environment, Forests and Climate Change are felled and replanted with species from a management plan.
• Experts assess soil quality and consult with the Kerala Forest Research Institute. Exotic species plantations are being converted to indigenous species for ecological benefits.

Issue with the Order:

• 2021 Eco-restoration Policy: Aimed to address invasive species and natural forest depletion, which increased human-wildlife conflict. It suggested replacing exotic plants with native species to support wildlife.
• Chinnakanal Example: A study indicated that replacing eucalyptus with native species could provide food for wild elephants, reducing human-animal conflicts.
• Policy Conflict: Environmental activists argued that the order to plant eucalyptus contradicted the eco-restoration policy, which prioritized eradicating invasive species and restoring natural habitats.

What is Ecological Restoration?

• The UN define ecosystem restoration as “the process of halting and reversing degradation, resulting in improved ecosystem services and recovered biodiversity”.
• In practice, a particular restoration can involve quite different transitions, depending on what best suits the local conditions.

Eco-restoration Efforts:

• Goal: Phase out industrial plantations of eucalyptus, acacia, wattle, and pine by 2024, replacing them with natural forests.
• Examples:
  • Marayoor Sandal Division, Idukki (2019): Removal of exotic species on 108 hectares led to the restoration of active water streams after 30 years, supported by UNDP, NABARD, and CAMPA.

About the Eucalyptus tree:

• Eucalyptus is an efficient biomass producer, which can produce more biomass than any other tree species.
• It is widely adopted by international wood companies and has become the ‘Green Gold’ of the pulp industry.
• It consumes less water per unit biomass produced than many other species of trees but due to the result of its fast growth and high biomass production, Eucalyptus species consume more water than other, less productive species.
• Growing Eucalyptus in low rainfall areas becomes the reason for adverse environmental impacts due to competition for water with other species and hence it increases the incidence of allelopathy. Generally, the areas which receive an annual rainfall of less than about 400 mm are not ideal for Eucalyptus wood production purposes due to this reason.
• The eucalyptus tree is one of the champions of biomass production. These trees lend themselves particularly well to genetic environment and biotechnologies, and so to farming intensification.
• However, eucalyptus reduces the water table significantly in the area where it grows apart from that it reduces the fertility of the soil nearby. Hence it is considered an ecological disaster.

Source: TH

6. Why dal imports have hit a seven-year high

Sub: Geography

Sec: Eco geography

Tag: dal imports

Context:

• In April 2024, the consumer price index for cereals rose by 8.63% compared to April 2023.

Details:

• Despite this, the price increase for roti has not significantly impacted the majority of poor and lower middle-class Indians due to the government’s food security scheme, which provides 5 kg of rice or wheat monthly to approximately 813.5 million people for free.

Pulse Inflation:

• However, the inflation in pulses, which recorded an annual retail inflation of 16.84% in April 2024, has severely affected consumers.
• Unlike cereals, pulses are not widely distributed through the public distribution system, forcing low-income households to rely heavily on open-market purchases.
• The price of chana (chickpea), the cheapest dal, rose from Rs 70 to Rs 85 per kg, while arhar/tur (pigeon pea) increased from Rs 120 to Rs 160 per kg.
• Prices for urad (black gram) and moong (green gram) also saw rises, whereas masoor (red lentil) prices slightly decreased.

Causes of this inflation:

• The primary cause for the surge in dal prices is the El Niño-induced irregular monsoon and winter rains, which led to a drop in domestic pulses production from 27.30 million tonnes in 2021-22 to 23.44 million tonnes in 2023-24.
• Significant production declines were observed in chana and arhar/tur, with chana production dropping from 13.54 million tonnes in 2021-22 to an estimated less than 10 million tonnes in 2023-24, and arhar/tur from 4.22 million tonnes to below 3 million tonnes.
• These poor harvests, particularly in Karnataka, Maharashtra, Andhra Pradesh, and Telangana, have driven chana and arhar/tur prices well above their minimum support prices (MSP) (Rs 5,440 for chana dal and Rs 7,000 per quintal for tur/arhar dal).

Import of pulses:

• As a result, India’s pulses imports surged, reaching $3.75 billion in 2023-24, the highest since 2016-17, with major pulse imports totalling 4.54 million tonnes, up from the preceding two fiscal years.

*Look out for the trends of imports from the chart.

Reversal of improved pulse production:

• The resurgence in imports marks a reversal of the relative self-sufficiency achieved by the country, with domestic pulses production increasing from 16.32 mt to 27.30 mt between 2015-16 and 2021-22.
• That was enabled by government policy measures incentivising farmers to grow pulses.
• These included MSP-based procurement and levying of duties leading to a near stoppage of imports, particularly of yellow/white peas (matar) and chana, by 2022-23.
• Domestic production got a further boost with the breeding of short-duration chana and moong varieties, making it possible to cultivate these with little or no irrigation, using the residual soil moisture left by the previous crops.
• The 50-75 day varieties of moong now allow planting of as many as four crops a year: kharif (post-monsoon), rabi (winter), spring and summer.

Government policy to reduce food inflation:

• Government policy responses to tackle food inflation included lifting tariffs and quantitative restrictions on pulse imports. 
• These measures were partly due to El Niño and electoral pressures to control dal prices.
• For instance, restrictions on yellow/white pea imports and tariffs on chana were removed, boosting imports from countries like Canada, Australia, Russia, and Africa.

Future prospects:

• The future of dal prices depends on the upcoming southwest monsoon.
• Climate models suggest a possible transition from El Niño to La Niña, which could bring good rainfall.
• However, given the low domestic supply and monsoon uncertainties, higher imports are expected to continue.
• The government has allowed duty-free imports of several pulses until March 31, 2025, and may need to extend this for yellow/white peas beyond October 31, 2024.
• Imports of these cheaper pulses are likely to increase, substituting more expensive varieties in the market.

Source: IE