CGPSC MAINS 2021 Paper-4

Points to Remember: The IUCN Red List uses several categories to classify threatened species. Each category represents a different level of extinction risk. Understanding these categories is crucial for conservation efforts. Introduction: The International Union for Conservation of Nature (IUCN) Red List of Threatened Species is a comprehensive inventory of the global conservation status of … Read more

Points to Remember: Definition and scope of solid waste management (SWM). Objectives of effective SWM. Functional elements of SWM (collection, transportation, processing, disposal). Challenges and best practices in SWM. Introduction: Solid waste management (SWM) encompasses the collection, transportation, processing, recycling, and disposal of solid materials that are discarded by individuals, businesses, and institutions. It’s a … Read more

Points to Remember: Biodiversity encompasses the variety of life at all levels, from genes to ecosystems. Genetic diversity refers to variations within a species. Species diversity refers to the number and abundance of different species. Ecological diversity refers to the variety of habitats, communities, and ecological processes. Introduction: Biodiversity, a contraction of “biological diversity,” refers … Read more

Points to Remember: Law of Reflection: Angle of incidence equals angle of reflection. Plane mirrors: Produce virtual, upright, and laterally inverted images of the same size as the object. Concave mirrors: Can produce real or virtual, inverted or upright images, depending on object position; converging mirrors. Convex mirrors: Always produce virtual, upright, and diminished images; … Read more

Points to Remember: Halogens are Group 17 elements. They are highly reactive non-metals. They exhibit a gradation in properties down the group. Interhalogen compounds are formed between different halogen atoms. Introduction: Halogens, meaning “salt-formers,” are a group of non-metal elements found in Group 17 (VIIA) of the periodic table. They include fluorine (F), chlorine (Cl), … Read more

Points to Remember: Photochemical smog is a type of air pollution. It forms through a complex series of chemical reactions involving sunlight, nitrogen oxides, and volatile organic compounds (VOCs). It has significant negative impacts on human health and the environment. Control strategies focus on reducing emissions of precursor pollutants. Introduction: Photochemical smog, also known as … Read more

Points to Remember: Basic components of a solar cell: p-type semiconductor, n-type semiconductor, metal contacts. Functionality based on the photovoltaic effect. Importance of anti-reflective coatings and encapsulation. Introduction: A solar cell, also known as a photovoltaic (PV) cell, is an electronic device that converts light energy directly into electricity. This conversion is based on the … Read more

Points to Remember: The spinal cord is a cylindrical structure extending from the brainstem. It’s the main pathway for information between the brain and the body. The nervous system comprises the central nervous system (CNS) and the peripheral nervous system (PNS), with the spinal cord being a crucial part of the CNS. Major components include … Read more

Points to Remember: This is a problem of profit sharing based on investment and time. The share of profit is directly proportional to the product of investment and time period. Introduction: This question involves calculating the profit share of three partners in a business based on their individual investments and the duration of their involvement. … Read more

Points to Remember: This is a mathematical word problem involving speed, time, and distance. The core concept is the relationship between speed, time, and distance (Distance = Speed × Time). We need to set up and solve a system of equations to find the speeds of the two trains. Introduction: This question is a classic … Read more