CGPSC MAINS 2017 Paper-4

Points to Remember: Resistance is opposition to the flow of current. Specific resistance is a material property. Factors affecting resistance are material properties, geometry, and temperature. Introduction: Electrical resistance is a fundamental concept in physics and electrical engineering. It quantifies the opposition a material offers to the flow of electric current. A material with high … Read more

Points to Remember: Minerals are naturally occurring, inorganic solids with a definite chemical composition and crystalline structure. Ores are minerals or rocks containing valuable substances that can be extracted profitably. The key difference lies in economic viability: a mineral becomes an ore when it’s economically feasible to extract the valuable substance. Introduction: Minerals and ores … Read more

Points to Remember: Definition of reaction rate Factors affecting reaction rate Units of reaction rate Importance of understanding reaction rates Introduction: Chemical reactions are the foundation of chemistry, governing everything from biological processes within our bodies to industrial manufacturing. Understanding the rate at which these reactions proceed is crucial for controlling and optimizing these processes. … Read more

Points to Remember: pH scale and its logarithmic nature. Strong acid dissociation. Calculation of pH using the formula: pH = -log₁₀[H⁺]. Introduction: The question requires a factual and analytical approach to calculate the change in pH of pure water upon addition of a strong acid like HCl. Pure water has a neutral pH of 7 … Read more

Points to Remember: Reliability and consistency of energy supply. Environmental impact (emissions, pollution). Economic viability (cost-effectiveness, job creation). Energy security (dependence on foreign sources). Technological feasibility and scalability. Social acceptability (public perception, community impact). Introduction: The term “good source of energy” is relative and depends on a multitude of factors. There is no single perfect … Read more

Points to Remember: Convex mirrors provide a wider field of view. Convex mirrors produce smaller, virtual, and erect images. The reduced image size helps in accommodating a larger area in the mirror’s view. The virtual and erect image is easier to interpret. Introduction: Rear-view mirrors are crucial for safe driving, providing drivers with a visual … Read more

Points to Remember: Brønsted-Lowry definition of acids and bases. Examples of Brønsted-Lowry acids and bases. Proton (H⁺) transfer as the central concept. Introduction: The understanding of acids and bases has evolved over time, with various definitions proposed. One of the most widely used definitions is the Brønsted-Lowry theory, which expands upon the earlier Arrhenius definition. … Read more