CGPSC MAINS 2020 Paper-4

Points to Remember: Depreciation is the decrease in the value of an asset over time. Straight-line depreciation and declining balance depreciation are common methods. This problem uses a declining balance method (compound depreciation). The formula for compound depreciation is: Future Value = Present Value * (1 – depreciation rate)^number of years Introduction: Depreciation is a … Read more

Points to Remember: Order of operations (PEMDAS/BODMAS): Parentheses/Brackets, Exponents/Orders, Multiplication and Division (from left to right), Addition and Subtraction (from left to right). Fraction addition/subtraction: Requires a common denominator. Fraction multiplication: Multiply numerators and denominators separately. Converting improper fractions to mixed fractions: Divide the numerator by the denominator; the quotient is the whole number part, … Read more

Points to Remember: Definition and types of detergents. Comparison of detergents and soaps in terms of cleaning effectiveness, water hardness, and environmental impact. Examples of detergents and their applications. Introduction: A detergent is a surfactant or a mixture of surfactants with “cleaning properties” in dilute solutions. Unlike soaps, which are salts of fatty acids, detergents … Read more

Points to Remember: Ohm’s Law: V = IR (Voltage = Current x Resistance) Series Resistance: Rtotal = R1 + R2 + … Parallel Resistance: 1/Rtotal = 1/R1 + 1/R2 + … Introduction: This question requires a factual and analytical approach to determine the equivalent resistance between points A and B in a given circuit. The … Read more

Points to Remember: The human brain is a complex organ with several distinct parts, each responsible for specific functions. Understanding these parts helps us appreciate the intricate workings of the mind. Introduction: The human brain, the command center of the body, is arguably the most complex organ known. Weighing approximately 3 pounds, it’s responsible for … Read more

Points to Remember: Pollination precedes fertilization. Fertilization involves the fusion of male and female gametes. Double fertilization is unique to angiosperms. The process leads to seed and fruit development. Environmental factors influence fertilization success. Introduction: Plant fertilization is the crucial process in sexual reproduction where the male gamete (sperm) unites with the female gamete (egg) … Read more

Points to Remember: Definition and legal basis of a National Park. Key characteristics and features of National Parks. Management and conservation challenges. Benefits and socio-economic impacts. Examples of successful National Parks globally. Introduction: A National Park is a protected area of national significance, designated by a government to preserve its natural and cultural heritage for … Read more

Points to Remember: Definition of α-biodiversity. Its relationship to other biodiversity levels (β and γ). Importance of α-biodiversity in conservation efforts. Measurement and assessment of α-biodiversity. Introduction: Biodiversity, encompassing the variety of life on Earth, is often categorized into three hierarchical levels: α, β, and γ diversity. Understanding these levels is crucial for effective conservation … Read more

Points to Remember: The severity of oil pollution in marine environments. The diverse sources of oil pollution (accidental spills, operational discharges, natural seeps). The multifaceted nature of solutions requiring technological, regulatory, and international cooperation. Introduction: Marine oil pollution is a significant environmental problem with devastating consequences for marine ecosystems and coastal communities. Oil spills, whether … Read more

Points to Remember: Environmental ethics is a branch of applied ethics. It deals with moral obligations towards the environment. It considers the intrinsic value of nature and its components. Different ethical perspectives influence environmental decision-making. Practical applications include conservation, pollution control, and sustainable development. Introduction: Environmental ethics is a rapidly evolving field that explores the … Read more