[DAY 41] 60 DAY RAPID REVISION (RaRe) SERIES for UPSC Prelims 2024 – SCIENCE AND TECHNOLOGY, CURRENT AFFAIRS & CSAT TEST SERIES!

Solution (b)

Rainbow is a natural spectrum. It is caused by dispersion (i.e., splitting of white light into seven constituent colors VIBGYOR) of sunlight by tiny droplets of water present in the atmosphere.

The most familiar example of dispersion is a rainbow, in which dispersion causes the spatial separation of a white light into components of different wavelengths (different colors).

Solution (a)

The air pressure at high altitudes is less than at ground level, so, the balloon will expand until the pressure inside equals the pressure outside. Consequently, the size will increase and at some point, it will burst.

Solution (b)

Incandescent Electric Bulb and Fluorescent Light Bulb

• An incandescent lamp generates light when electric current heats a tungsten filament wire so that it glows, or incandesces.
• Fluorescent bulbs generate light by sending an electrical discharge through an ionized gas.
• Materials used in Fluorescent: Argon, mercury vapor, tungsten, barium, strontium and calcium oxides.
• Materials used in Incandescent: Argon, tungsten filament.
• The efficacy of incandescent bulbs is low which is a major disadvantage in terms of higher operating costs and more heat in the room.
• Fluorescent is a very energy efficient light source that enjoys low operating costs and contributes little heat to the room.

Solution (c)

Heat is measured in terms of Joule (J) since it is energy. Celsius is used to measure temperature. All other options are correctly matched.

Solution (c)

• An electric motor is a rotating device that converts electrical energy to mechanical energy. Electric motor is used as an important component in electric fans, refrigerators, mixers, washing machines, computers, MP3 players etc.
• A device that reverses the direction of flow of current through a circuit is called a commutator.
• A galvanometer is an instrument that can detect the presence of a current in a circuit.

Solution (b)

Atmospheric pressure decreases with increase in altitude.

As we go higher, the pressure within the blood vessels exceeds the external pressure. This causes the blood vessels to burst. Consequently, we suffer nose bleeding, ear bleeding etc.

Solution (d)

Solution (c)

Scattering of a beam of light is called the Tyndall effect after the name of the scientist who discovered this effect. Tyndall effect can also be observed when a fine beam of light enters a room through a small hole. This happens due to the scattering of light by the particles of dust and smoke in the air.

Solution (d)

Electromagnet

• Electromagnet- device consisting of a core of magnetic material surrounded by a coil through which an electric current is passed to magnetize the core.
• The electromagnets are the magnets that are created when the electric current is passed through it. These electromagnets have immense applications in everyday life and every industry.
• The strength of the electromagnets can be altered by repeated variation in the amount of electric current that flows through them.
• Applications in:
  • Electric Bells and Buzzers
  • Loudspeakers
  • Cranes in Lifting
  • MRI machines
  • Tape Recorders, Hard Disks etc.
  • Microwaves
  • Transformers
  • Microphones
  • Optical Instruments
  • Pendrive etc.

Solution (b)

When the speed of any object exceeds the speed of sound it is said to be travelling at supersonic speed. Bullets, jet aircrafts etc. often travel at supersonic speeds. When a sound, producing source moves with a speed higher than that of sound, it produces shock waves in air. These shock waves carry a large amount of energy. The air pressure variation associated with this type of shock waves produces a very sharp and loud sound called the “sonic boom”. The shock waves produced by a supersonic aircraft have enough energy to shatter window glass and even damage buildings.

Solution (b)

Solution (c)

Electricity flows in two ways: in an alternating current (AC) or in a direct current (DC).

• Electricity is nothing but the movement of electrons through a conductor
• In DC, the electrons flow steadily in a single direction, or forward.
• In AC, electrons keep switching directions.
• Alternating current is the best way to transmit electricity over large distances. D.C current does not travel safely over a long distance because D.C current loses much energy as compared to A.C.
• The frequency of alternating current is 50Hz or 60Hz depending upon the country. The frequency of direct current is zero.
• The magnitude of alternating current varies with time. The magnitude of D.C current does not vary with time.
• C current is produced mainly by Generators. D.C current is produced from battery or cell etc.
• In A.C current power factor always lies between 0 to 1. In D.C current power factor always remains 1.
• AC is used in homes, industries, etc. DC is used in refrigerators, TV, etc.

Solution (b)

Refractive Index

Refractive Index, also called index of refraction, measure of the bending of a ray of light when passing from one medium into another. The refractive index can be linked to an important physical quantity, the relative speed of propagation of light in different media.

It turns out that light propagates with different speeds in different media.

• Light travels the fastest in vacuum with the highest speed of 3×10^8 m s–1.
• In air, the speed of light is only marginally less, compared to that in vacuum.
• It reduces considerably in glass or water.
• The value of the refractive index for a given pair of media depends upon the speed of light in the two media.
• The refractive index is dimensionless.
• The refractive index, represented by symbol n, is the velocity of light in vacuum divided by the velocity of light in a medium.
• Formula: n=c/v
  • n is the refractive index
  • c is the velocity of light in a vacuum (3 × 10^8 m/s)
  • v is the velocity of light in a substance
• Higher the refractive index, the higher the optical density and slower is the speed of light.

Solution (b)

Solution (b)

Solution (c)

Solution (a)

Solution (a)

Solution (a)

Solution (d)

Solution (b)

• The Production Linked Incentive Scheme (PLI) aims to scale up domestic manufacturing capability, accompanied by higher import substitution and employment generation. Hence statement 1 is correct.
• It is currently active in 14 key sectors – mobile manufacturing, manufacturing of medical devices, automobiles and auto components, pharmaceuticals, drugs, specialty steel, telecom & networking products, electronic products, white goods (ACs and LEDs), food products, textile products, solar PV modules, advanced chemistry cell (ACC) battery, and drones and drone components. Hence statement 2 is incorrect.
• It provides financial rewards to domestic and foreign companies for manufacturing in India, based on a percentage of their revenue over up to five years. Hence statement 3 is correct.

Solution (b)

• The Mahakaleshwar Temple is situated beside the Rudra Sagar Lake in Madhya Pradesh. Hence statement 1 is incorrect.
• The temple complex comes with a spacious courtyard that is adorned with the finest sculptures that are believed to be influenced by the Chalukya, Maratha, and Bhumija styles of structural design.
• It is a Hindu temple dedicated to Shiva and is one of the twelve Jyotirlingams. Hence statement 2 is correct.
• The images of Ganesh, Parvati, and Karttikeya are installed in the west, north, and east of the sanctum sanctorum.
• Its idol is Dakshina Mukhi, facing south, unlike all the other Jyotirlingas. Hence statement 3 is correct.
• The temple also houses a tank constructed in the Sarvatobhadra style.

Solution (a)

• The Pravasi Bharatiya Diwas is celebrated on January 9 to mark the contribution and achievements of the overseas Indian community to the development of India. Hence statement 1 is correct.
• It commemorates the return of Mahatma Gandhi, the greatest Pravasi, from South Africa to India in 1915, who led India’s freedom struggle and changed the lives of Indians forever.
• It was first celebrated in 2003. It was an annual event earlier, but in 2015, the government revised its format to celebrate PBD once every two years.
• It is the flagship event of the Ministry of External Affairs. Hence statement 2 is incorrect.
• It has become a platform to connect the Indian diaspora with their roots and encourage their continued engagement with India’s progress.
• It is held in different cities, to showcase the diversity and progress of different regions of Toa. To date, 17 conventions have been held. The last Pravasi Bharatiya Divas was celebrated in the Indore of Madhya Pradesh in 2023.

Solution (c)

• The Scheme for Residential Education for Students in High Schools in Targeted Areas (SHRESHTA) aims to provide access to the best private residential schools for meritorious students from Scheduled Caste (SC) communities. Hence statement 1 is correct.
• It will provide scholarships to meritorious students from SC communities to study in private and NGO-run residential schools for Classes 9-12.
• It is implemented by the Department of Social Justice and Empowerment, Ministry of Social Justice & Empowerment. Hence statement 2 is correct.
• The core objectives of the scheme are to enhance the reach of the development initiatives of the government and fill in the gap in service-deprived SC dominant areas in the education sector.
• The scheme will collaborate with voluntary organisations to provide an environment that can help create conditions for socio-economic upliftment and the overall development of the SC communities.
• Students whose annual parental income is less than Rs 2,50,000 and who belong to SC communities are eligible to participate in this scheme.
• Only those candidates who have passed or are appearing in Class VIII/X in the given academic session can apply for admission to Class IX/XI.

Solution (c)

• The International Classification of Diseases (ICD) is developed by the World Health Organization (WHO) to classify diseases internationally. Hence statement 1 is correct.
• The global data on diseases currently available is mainly based on healthcare practices to be diagnosed through modern biomedicine.
• It serves a broad range of uses globally and provides critical knowledge on the extent, causes, and consequences of human disease and death worldwide via data that is reported and coded with the ICD.
• Clinical terms coded with ICD are the main basis for health recording and statistics on disease in primary, secondary, and tertiary care, as well as on cause of death certificates.
• It facilitates the collection and dissemination of data on various diseases and mortality. Hence statement 2 is correct.
• These data and statistics support payment systems, service planning, administration of quality and safety, and health services research.
• Diagnostic guidance linked to categories of ICD also standardizes data collection and enables large-scale research.
• The classification of data and terminology relating to diseases based on Ayush systems such as Ayurveda, Siddha, Unani, etc. is not yet included in the WHO ICD series.
• In India, the Central Bureau of Health Intelligence (CBHI) under the Ministry of Health and Family Welfare serves as its collaborator. Hence statement 3 is correct.

Solution (c)

• The MCG-01-24-014 is a galaxy situated approximately 275 million light-years away from Earth in the constellation of Hydra. Hence statement 1 is correct.
• It boasts a well-defined structure and an extremely energetic core classified as an active galactic nucleus (AGN).
• It falls under the category of Type-2 Seyfert galaxies. Hence statement 2 is correct.
• Seyfert galaxies are any of a class of galaxies known to have active nuclei. They are one of the most common types of active galaxies, sharing the stage with the more distant and luminous quasars.

Solution (c)

• Kavaratti Island is located between Agatti Island on the west and Andrott Island on the east. Hence statement 1 is correct.
• It is the capital of Lakshadweep (the smallest Union Territory of India) and its most developed island.
• It lies 360 km off the coast of the State of Kerala.
• It is located in the centre of the Lakshadweep archipelago.
• It has been selected as one of the hundred Indian cities to be developed as a smart city under the flagship Smart Cities Mission. Hence statement 2 is correct.
• There is a shallow lagoon on the western side of the island, and coconut palms grow on the northern side.
• The island is home to 12 atolls, five submerged banks, and three coral reefs.
• It is noted for the carved wooden pillars and roofs of its mosques and the carved stones of its graveyards.

Solution (a)

• Chandubi Festival is organised every year along the Chandubi Lake in the state of Assam. Hence statement 1 is correct.
• The main attractions of the Chandubi festival are the local folk culture, ethnic cuisine, local handloom and dresses, boating, etc.
• The major aim of the Chandubi Festival is to promote eco-tourism in this biodiversity hotspot of Assam.
• Chandubi Lake is a freshwater lake that was created during a massive earthquake in the year 1897. Hence statement 2 is incorrect.
• The name Chandubi is derived from two words where Chand means five and Dubi means sinking in Khasi language.
• It was turned into an economically viable water body that would sustain different communities living around the lake.

Solution (b)

• Elasmobranch refers to the sharks, rays, and skates. Hence statement 1 is correct.
• They have five to seven-gill openings on each side.
• Spiracles aid in breathing.
• They have a skeleton made of cartilage, rather than bone. Hence statement 2 is incorrect.
• They have several rows of teeth which are continually replaced.
• Their skin is made of tiny, hard, tooth-like placoid scales called denticles.
• These are renowned for their highly tuned senses, which make them incredibly successful in their environment.
• They don’t have swim bladders, but instead, their large livers are full of oil to provide buoyancy. Hence statement 3 is correct.
• They reproduce sexually with internal fertilization and either bear live young or lay eggs.

Solution (b)

The vowels in the order presented are: E, U, A, I, O or perhaps better sorted as: A, E, I, O, U Think of the vowels as one block, and have some other letter (say X) representing that block. We go from the word EDUCATION to X,D,C,T,N

The initial 9 letter word drops to 9-5 = 4 letters after we kick out the vowels. Then introducing letter X brings the count up to 5 letters.

Anywhere you see an X, replace it with some permutation of A,E,I,O,U.

There are 5! = 5*4*3*2*1 = 120 ways to arrange X,D,C,T,N

And there are 5! = 120 ways to arrange the five vowels.

Overall, there are (5!)*(5!) = 120*120 = 14400 different arrangements such that the vowels stick together.

Solution (c)

• Sky Dew is a high-altitude observation balloon that acts as a detection radar blip for small unmanned aircraft and cruise missiles. Hence statement 1 is correct.
• It is one of the largest aerial threat warning systems in the world.
• It has been jointly developed by Israel Defense and US company TCOM. Hence statement 2 is correct.
• The project was entirely funded by the U.S. Department of Defence. The Israel Air Force was handed over the Sky Dew in 2022.
• The system comprises a blimp capable of flying at high altitudes with radar and detection systems to scan a wide range in any direction.
• The radar on the balloon is capable of observing at 250 km and tracking multiple targets, including low-altitude ones and those in valleys. It can carry 7,000 pounds and has an operational altitude of 10,000 feet.

Solution (c)

=> Single digit numbers: 1, 3 or 5: Three numbers
=> Two–digit numbers: Units digit = 1, 3 or 5. For the tens’ digit, there are 5 choices {anything apart from what went into the units digit}. So, there will be 3 × 5 = 15 such numbers.
=> Three–digit numbers: Units digit = 1, 3 or 5. For the tens’ digit, there are 5 choices {anything apart from what went into the units digit}. For the 100s’ digit, there are 4 choices {anything apart from what went into the units digit or tens digit}. So, there will be 3 * 5 * 4 = 60 such numbers.
=> 4–digit numbers: There will be 3 * 5 * 4 * 3 = 180 numbers.
=> 5–digit numbers: There will be 3 * 5 * 4 * 3 * 2 = 360 numbers.
=> 6–digit numbers: There will be 3 * 5 * 4 * 3 * 2 * 1 = 360 numbers.

Total number of numbers = 360 + 360 + 180 + 60 + 15 + 3 = 978

Solution (b)

For two players, we need one match.

The first round, having 256 players will need 256/2 = 128 matches.

Now there are 128 players left. To ensure that all players play a match, we need 128/2 = 64 matches

Continuing in the same way Total number of matches = 128+64+ 32+ 16+8+4+2+1= 255

OR

In 1 match 1 player is eliminated For tournament to conclude there should be only 1 winner and hence 255 players need to lose. Hence we need 255 matches to eliminate 255 players. Hence option (b).

Solution (d)

Zero is there when we have 2 x 5. This creates 10 and as many pairs of 2 x 5 are there we will have same number of zeros at the end.

Now, there are 10 twos in the series as there are 10 even numbers from 1 to 20. So, we need to check the number of fives. We have fives at 5, 10 (5 x 2), 15 (5 x 3) and 20 (5 x 2 x 2). So, the number of zeros at the end will be 4.

Solution (b)

If the overall average weight has to increase after the new people are added, the average weight of the new entrants has to be higher than 40.
So, n > 40

Consequently, m has to be < 10 (as n + m = 50)
Working with the “differences” approach, we know that the total additional weight added by “m” students would be (n – 40) each, above the already existing average of 40.

m(n – 40) is the total extra additional weight added, which is shared amongst 40 + m students.

So, m * (n−40)/(m+40) has to be maximum for the overall average to be maximum.

At this point, use the trial and error approach (or else, go with the answer options) to arrive at the answer

The maximum average occurs when m = 5, and n = 45
And the average is 40 + (45 – 40) * 5/45 = 40 + 5/9 = 40.56 kgs