What is the SI unit of energy?A: Joule (J)Q: What is the principle behind the working of a lever?A: The principle of mechanical advantage, where a small force applied over a large distance can lift a heavy load over a short distance.Q: What is the difference between velocity and speed?A: Velocity includes both speed and direction, while speed is the magnitude of velocity.Q: What is Newton's first law of motion?A: An object will remain at rest or in uniform motion in a straight line unless acted upon by an external force.Q: What is the principle behind the working of a pulley system?A: The principle of mechanical advantage, where multiple pulleys reduce the amount of force required to lift a heavy object.Material Science:Q: What is the process of heat treatment used for metals?A: Heat treatment involves heating and cooling metals to alter their properties, such as hardness, toughness, and ductility.Q: What is the difference between ferrous and non-ferrous metals?A: Ferrous metals contain iron, while non-ferrous metals do not.Q: What is the composition of stainless steel?A: Stainless steel is primarily composed of iron, carbon, and chromium.Q: What is the process of annealing used for metals?A: Annealing involves heating metals to a specific temperature and then slowly cooling them to relieve internal stresses and increase ductility.Q: What is the function of alloying elements in metals?A: Alloying elements are added to metals to improve their mechanical properties, such as strength, hardness, and corrosion resistance.Environmental Science:Q: What is the greenhouse effect?A: The greenhouse effect is the process by which greenhouse gases trap heat in the Earth's atmosphere, leading to global warming.Q: What are the primary sources of air pollution?A: The primary sources of air pollution include vehicle emissions, industrial processes, and burning of fossil fuels.Q: What is the ozone layer, and why is it important?A: The ozone layer is a region of the Earth's stratosphere that contains a high concentration of ozone molecules. It is important because it absorbs harmful ultraviolet (UV) radiation from the sun, protecting life on Earth.