Daily Prelims 23rd February 2024

Prelims Booster

1. Rhodamine – B

• It is a water-soluble chemical compound. 
• While it appears green in powder form, it turns vivid fluorescent pink when it comes in contact with water. 
• It is a chemical commonly used for dyeing in the textile, paper, leather, and paints industry as a coloring agent that helps in attaining the red and pink spectrum. 
• “As per the Food Safety Standards Act, 2006, preparation, packaging, importing, selling and serving food items with Rhodamine-B in wedding ceremonies and other public events is a punishable offence. 
• It is an industrial dye which is not allowed in food anywhere in the world as it is toxic. 

Why is it harmful? 

• Researchers have identified that if food containing this chemical is consumed regularly, it can cause damage to the cerebellum tissue in the brain and to the brainstem that connects the brain to the spinal cord. 
• These damages can lead to functional abnormalities and can hinder humans’ motor functioning.  
• The chemical is toxic for humans and can cause oxidative stress on cells and tissues if ingested. 
• It becomes particularly hazardous when it is mixed with food products, leading to cancer and tumour over time.

2. Quasar :

• A quasar is an extremely active and luminous type of active galactic nucleus (AGN).  
• An AGN is nothing more than a supermassive black hole that is activeand feeding at the center of a galaxy.  
• All quasars are AGNs, but not all AGNs are quasars. 
• Quasars are thought to form in regions of the universe where the large-scale density of matter is much higher than average. 
• They are among the most luminous, powerful, and vibrant objects known in the universe. 
• How are they formed? 

• • An active galaxy is one in which the central supermassive black hole is consuming large amounts of matter. 

• • The infall of matter into the black hole is so great that all the material can’t enter the black hole at the same time, so it forms a queueas a spiraling accretion disk.  
  • The matter—in the form of huge clouds—falls into the disk, with the inner parts of the cloud closer to the black hole orbiting faster than the outer parts (just like planets closer to the sun orbit faster than those farther away).  
  • This creates a shear force that twists the clouds, causing them to bump into their neighbors as they move around the black hole at velocities ranging from 10% of the speed of light up to over 80%. 
  • This friction from fast-moving gas clouds generates heat, and the disk becomes so hot—millions of degrees—that it shines brightly.  
  • Some of the material in the disk is also funneled away from the black hole in a highly luminous, magnetically collimated jet. 
• The hot accretion disk and the jet combine to make the nucleus of the active galaxy shine so brightlythat it can be seen far across the universe. 

• The brightest quasars can outshine all of the stars in the galaxies in which they reside, which makes them visible even at distances of billions of light-years. 
• Most quasars have been found billions of light-years away. 

3. Morodharo:

• It is a fortified settlement dating back to the Harappan-era. 
• Location: Kutch District, Gujarat 
• Features: 

• • The settlement looks mature (2,600-1,900BCE) to late (1,900-1,300 BCE) Harappan. 
  • The fortification measures 102 m east to the west and 58 m north to the south. 
  • The thickness of the wall is an average of 3.3 m. 
  • It has a 10×10 m platform on the south-west side and a well on the north-east. 
  • Burial cairns, which are mounds of stones to demarcate a boundary, are also found here. 
  • Harappan pottery with perforated jar sherds, reserved slipware, and terracotta cakes were unearthed. All these items have a striking resemblance to those found in Dholavira. 

Key Facts about Harappan Civilization 

• The Indus Valley/Harappan civilisation was the first urban civilisation in South Asia, coexisting with Mesopotamia and Egypt. 
• The Harappan civilisation occupied the largest area (approximately 8,00,000 sq km) among the three civilisations. 
• Harappa (Punjab, Pakistan), Mohenjo-Daro (Sindh, Pakistan), Dholavira, Lothal, and Surkotada (Gujarat, India), Kalibangan and Banawali (Rajasthan, India), and Rakhigarhi (Haryana, India) are the major cities in the Harappan period.  
• The features of town planning of Harappan civilisation included:  
  • Rectangular grid pattern: The Harappan cities were designed on a grid pattern, with streets running in a north-south and east-west direction, forming a well-organized layout. Streets and lanes were cutting across one another almost at right angles, thus dividing the city into several rectangular blocks. 
  • Planned streets and alleyways: The streets and alleyways of Harappan cities were planned and constructed with precision. They were wide enough to allow the movement of carts and pedestrians, and some streets had covered drains running alongside them. 
  • Fortification: The cities were surrounded by fortified walls made of mud bricks, providing protection against robbers, cattle raiders, and floods.  
  • Division of cities: The city was divided into two parts: an upraised citadel and the lower part of the city.  
  • Upper part: An upraised citadel in the western part was used for constructing buildings of large dimensions, such as granaries, administrative buildings, pillared halls, and courtyards. 
  • Lower part: Below the citadel in each city lay a lower town containing brick houses, which were inhabited by the common people. 
  • Material used: They used burnt bricks on a large scale in almost all kinds of constructions, and there was the absence of stone buildings during Harappan culture. 
  • Residential areas: The cities were divided into distinct residential areas. Houses were made of baked bricks, often with multiple stories, indicating a well-developed urban society. The houses were generally built around courtyards, and some had private wells and properly ventilated bathrooms. No window faced the streets, and the houses had tiled bathrooms. 
  • Sophisticated drainage systems: The drainage system of the Harappans was elaborate and well laid out. Every house had drains, which opened into the street drains. Drains were made of mortar, lime, and gypsum. 
  • Granaries and storage facilities: The cities had well-planned granaries and storage facilities to store surplus agricultural produce.  

Places in News 

Gulf Of Aden 

• The Gulf of Aden, an arm of the Indian Ocean is situated between Yemen on the south coast of the Arabian Peninsula and Somalia in Africa. 
• It is bounded to the south by Somalia and the Socotra Islands, north by Yemen, east by the Arabian Sea, and west by Djibouti. 
• The gulf – roughly 900 kilometers long and 500 kilometers wide is an important waterway for transporting Persian Gulf oil. 
• The gulf connects the Red Sea to the Arabian Sea via the Strait of Bab el Mandeb. It forms an essential oil transport route between Europe and the Far East. 
• Its marine life is rich in quantity and variety. Its coastline lacks large-scale fishing facilities but supports many fishing towns, as well as the major ports Aden and Djibouti. 
• In recent years, the gulf has received a lot of attention due to piracy, terrorism and refugee smuggling.