Railway Science (Physics-Miscellaneous)

Scalar Quantity - A scalar quantity is defined as the physical quantity with only magnitude and no direction. Example - speed, distance, mass, etc. Vector quantity - The physical quantity in which both quantity (magnitude) and direction are contained. Examples - velocity, force, momentum, etc.

A magnet is any object that produces its own magnetic field that interacts with other magnetic fields. Magnets have two poles, a north pole and a south pole. There are typically four categories of permanent magnets: Neodymium iron boron, Samarium cobalt, Alnico, and Cera

It is the product of mass (m) and velocity (v). Conservation of momentum: Whenever there is no net external force on the system then the total momentum of the system remains constant. It means Initial momentum = Final momentum. Rocket ejects gases in the backward direction and so it moves forward so as to conserve the momentum. Examples of Linear momentum - A Gun's Recoil, Motorboats etc.

SAR (Specific Absorption Rate) is a measure of the amount of radio frequency energy absorbed by the body from a source. Unit  - 𝑊𝑎𝑡𝑡/𝐾𝑔. SAR value information is displayed on the mobile handsets like IMEI (International Mobile Equipment Identity) display.

(Gallium Arsenide): It has a high energy conversion efficiency, making it an excellent material for converting sunlight into electricity. It is commonly used as a substrate of other semiconductors. Other semiconductor materials used in solar panels are: Silicon (Si), Tin Oxide (SnO).

Examples of translucent materials: Frosted glass, wax paper, sunglasses and vegetable oil. Transparent materials allow objects on the other side of a transparent material to be seen clearly. Examples: Glass, Water, Air. Opaque materials do not allow any light to pass through it. Examples: wood, metal, and stone. Lustrous materials, those materials that have shiny surfaces. Examples: Silver, Aluminium, Gold.

(An Italian Astronomer). He is often referred to as the “Father of modern Astronomy”. Stephen Hawking (British theoretical Physicist) - known for his work on black holes and the Big Bang. CV Raman (Indian Physicist): Awarded by Nobel Prize (Physics, 1930) for his work on the scattering of light. Vikram Sarabhai (Indian Scientist) - Father of the Indian space program.

Van Der Waals force is an intermolecular force that attracts neutral molecules to one another. Examples of van der Waals Force - Polymer Formation, Protein Structure, Water Droplets. The Electromagnetic force is a physical interaction that happens when electrically charged particles interact with each other. Example - Chemical Bond, Magnets and the Earth's magnetic field. Coulomb’s force, also known as electrostatic force, is the attraction or repulsion force between two electric charges. Example - Rubbing a rod with a cloth, Rubbing a Balloon on a person's hair, and Charged Comb.

It is the measure of Inertia. Its SI unit is kg. It is a scalar quantity. Mass always stays the same, but weight can change depending on how much gravity is acting upon an object. Weight is a vector quantity and its SI unit is Newton. Formula of weight = mass × acceleration due to gravity. The gravity on the moon is one-sixth of the Earth.

It is a device that uses a catalyst to convert three (Unburned hydrocarbons, Nitrogen oxides, Carbon monoxides) harmful compounds into harmless compounds like carbon dioxide and water. Carburetor - The part of a Spark Ignition engine that mixes fuel and air in a certain ratio. Radiator - A radiator is an important component of an engine's cooling system which helps in keeping the engine temperature optimum. It provides cool air to the engine by circulating a mixture of antifreeze and water that does not cause the engine to overheat.