Which device converts AC to DC?

General Science covers basic concepts in Physics, Chemistry, Biology, and Earth Science. It is an important section in competitive exams like SSC CGL, UPSC Prelims, Railway NTPC, and Defence exams. Questions include scientific laws, inventions, human body systems, chemical reactions, and everyday science phenomena. NCERT Science books from Class 6 to 10 are recommended.

Newton's Three Laws of Motion: 1) First Law (Law of Inertia) - An object remains at rest or in uniform motion unless acted upon by an external force. 2) Second Law - Force equals mass times acceleration (F=ma). 3) Third Law - For every action there is an equal and opposite reaction. These laws are fundamental to Physics and frequently asked in SSC CGL, Railway, and NDA exams.

A conductor allows electric current to flow freely through it. Examples: copper, aluminium, silver. An insulator does not allow electric current to flow. Examples: rubber, wood, glass, plastic. Semiconductors like silicon fall between conductors and insulators and are used in electronic devices. This topic is important for SSC and Railway technical exams.

Human blood consists of: Red Blood Cells (RBCs) that carry oxygen using hemoglobin, White Blood Cells (WBCs) that fight infections, Platelets that help in blood clotting, and Plasma (liquid component, about 55% of blood) that carries nutrients, hormones, and waste products. Normal blood pH is 7.35-7.45.

Photosynthesis is the process by which green plants use sunlight, water, and carbon dioxide to produce glucose and oxygen. The chemical equation is: 6CO2 + 6H2O + Light Energy gives C6H12O6 + 6O2. Chlorophyll in leaves absorbs sunlight. Photosynthesis occurs in two stages: Light reactions (in thylakoids) and Dark reactions/Calvin cycle (in stroma).