Physical Sciences
• A mixture of two metals is called an “Alloy.”
• An extremely small piece of silicon on which integrated circuits are fabricated is called a “Chip.”
• The main cause of earthquakes is “Tectonic plates’ movement.”
• The percentage of Oxygen in the air is “21%.”
• When the acid is dissolved in a lot of water, it is called “Dilute acid.”
• The substance that reacts with an acid to give a salt is called a “Base.”
• The reaction when alkalis react with acids to give salt is called “Neutralization.”
• The acid contained by our stomach to digest food is “Hydrochloric acid.”
• Fruits like lemon taste sour due to the presence of “Citric acid.”
• Vinegar tastes sour due to the presence of “Acetic acid.”
• Polluting rain caused by the combining of oxides of sulfur and nitrogen with atmospheric moisture is known as “Acid rain.”
• The freezing point of heavy water is “1.82 °C.”
• The occurrence of an element in two or more forms that differ in their crystalline or molecular structure is called “Allotropy.”
• The substance made of a mixture of two or more metals is called an “Alloy.”
• Brass is the mixture of “Copper and zinc.”
• The flow of electrically charged particles through a conducting circuit due to the presence of a potential difference is called “Electric Current.”
• The electric current that flows for an interval of time in one direction and then in the opposite direction is called “Alternating current (AC).”
• The electric current that flows in one direction and does not reverse its flow is called “Direct current (DC).”
• When heat is sufficiently intense, and the conductor is strong enough, radiation is produced.
• When mercury is combined with other metals, the alloy formed is called “Amalgam.”
• Annual rings are circular rings on trees of a temperate region.
• Asbestos is used for insulation and protection from fire, heat, and electricity because heat and electricity cannot pass through them easily.
• A bomb that derives its explosive force from nuclear fission is called an “Atom bomb.”
• Energy released through the fission or fusion of atomic nuclei is known as “Nuclear Energy.”
• A nuclear reactor is a device for producing nuclear energy in a controlled manner.
• Nuclear waste includes radioactive and toxic by-products of both nuclear energy and the nuclear-weapon industry.
• The center of an atom, containing particles called protons and neutrons, is called the “Nucleus.”
• The lightest particle in the atom is the “Electron.”
• The positively charged particle in the nucleus of an atom is the “Proton.”
• The substance that cannot split chemically into simpler substances is an “Element.”
• Elements with atomic numbers from 96 to 109, synthesized only in particle accelerators, are called “Heavy elements.”
• The two particles in the nucleus of an atom are called “Subatomic particles.”
• A negatively charged particle that moves around the nucleus of an atom in orbits is the “Electron.”
• The simplest and lightest atom is the “Atom of Hydrogen.”
• The atomic number of an element is the number of “Protons in its nucleus.”
• Elements are grouped by their atomic number in a table called the “Periodic table.”
• An atom or group of atoms that is either positively charged or negatively charged due to the loss or gain of electrons is called an “Ion.”
• In the nuclear reaction where an atom is split into two approximately equal masses, it is called “Fission.”
• The fusing of the nuclei of light elements into heavier elements is called “Fusion.”
• The device that produces electricity from chemicals is a “Battery.”
• A car battery contains “Lead-acid cells or lead accumulators.”
• The temperature at which a liquid turns into a vapor or gas is known as the “Boiling point.”
• The temperature at which a liquid changes to a solid is called the “Freezing point.”
• Calcium phosphate is used in “Fertilizers.”
• Calcium compounds cause “Hardness of water.”
• A group of chemical compounds that contains carbon, hydrogen, and oxygen only, with a ratio of hydrogen to oxygen atoms usually 2:1, is called “Carbohydrate.”
• Carbon is the most important element as it is found in all living matters and occurs naturally in the form of diamond and graphite.
• Cast Iron is cheap but invaluable in construction and is commonly used for car engine blocks.
• Centrifugal and centripetal forces act on a body as it moves along a “Curved path.”
• Objects made from clay and hardened into a permanent form by baking (firing) at very high temperatures in a kiln are called “Ceramics.”
• In nuclear physics, a fission reaction that is maintained because neutrons released by the splitting of some nuclei themselves go on to split others, releasing even more neutrons is called a “Chain reaction.”
• The process in which substances combine or are broken down to form new substances is called a “Chemical reaction.”
• The yellowish-green gas that has a strong, choking smell and is often added to water to kill germs is “Chlorine.”
• Chlorofluorocarbon is odorless, non-toxic, non-flammable, and chemically inert. It is used in aerosol cans, refrigerators, and air conditioners, and for foam packing.
• The cell or organism genetically identical to the cell or organism from which it has been derived is called a “Clone.”
• The cables used in the transmission of TV, telephone, and telegraph signals consist of two conductors, one within the other, separated by an insulator. These cables are called “Coaxial cable.”
• The group of three primary colors are “Red, Green, Blue.”
• When red, green, and blue are mixed together equally in paints and inks, they look “White.”
• A material that conducts heat or electricity is called a “Conductor.”
• The mixture in which one substance is suspended in another is called a “Colloid.”
• The process of separation of a substance in a colloid is called “Dialysis.”
• An artificial earth-orbiting object used to relay radio signals between points on Earth is called a “Communication Satellite.”
• The orbits of most communication satellites are located at a height above the equator of “33,900 km.”
• When two or more elements are joined together, they are called a “Solid.”
• The mass of an object divided by its volume is called “Density.”
• A substance used to remove dirt and grease but, unlike soap, does not form a thin layer of scum on the surface of water is “Detergent.”
• The optical phenomenon where a beam of white light is broken up into its component colors when it passes through a triangular glass prism is called “Dispersion.”
• Water, being a compound, contains the elements “Hydrogen and oxygen.”
• The term “concave” of a surface means “Curving inward.”
• The change of a gas into a liquid when it is cooled is called “Condensation.”
• Electromagnetic waves with long wavelengths used to send signals around the Earth are known as “Radio and television waves.”
• A moving electron causes “Current electricity.”
• Things like electricity, sound, light, and heat, which do not have mass or volume, are called “Energy.”
• Waves with a shorter wavelength than light are called “All of these” (Gamma rays, X-rays, Ultra-violet waves).
• The red-brown metal that was the first metal used to make tools and weapons and is a very good conductor of heat and electricity is “Iron.”
• The machine that transforms energy into useful mechanical work is called an “Engine.”