General Physics

Concave lens possesses at least one surface that curves inwards. It is a diverging lens, spreading out those light rays that have been refracted through it. A concave lens is thinner at its centre than at its edges, and is used to correct short-sightedness (myopia).

Details

Heavy water, formally called deuterium oxide or 2H2O or D2O, is a form of water that contains the hydrogen isotope deuterium, rather than the common protium isotope. The colloquial term heavy water is often also used to refer a highly enriched water mixture that contains mostly deuterium oxide but also contains some ordinary water molecules as well: for instance heavy water used in CANDU reactors is 99.75% enriched by hydrogen atom-fraction

Convection transfers heat vertically into the atmosphere. In order for heat to be transferred to other regions, it must be transferred horizontally by the wind. The horizontal transfer of heat by the wind is called advection.

The quantity of impulse is force × time interval. In classical mechanics, linear momentum or translational momentum is the product of the mass and velocity of an object. For example, a heavy truck moving fast has a large momentum—it takes a large and prolonged force to get the truck up to this speed, and it takes a large and prolonged force to bring it to a stop afterwards. If the truck were lighter or moving slower, then it would have less momentum.

Radius of a capillary tube is inversely proportional to the height of the liquid column. So, if radius of the tube is doubled, rise of level of water will becomes half of the previous rise in capillary tube. Capillary action, or capillarity, is the ability of a liquid to flow in narrow spaces without the assistance of, and in opposition to external forces like gravity.

The mass of a star which is two times the mass of the sun turns into a neutron star. A neutron star is a type of stellar remnant that can result from the gravitational collapse of a massive star during a Type II, Type Ib or Type Ic supernova event. Such stars are composed almost entirely of neutrons, which are subatomic particles without electrical charge and with slightly larger mass than protons.

Indigo is a dye different than any other. It does not require any mordant. Rather it is dyed through a living fermentation process. The process “reduces” the Indigo, changing it from blue to yellow. In this state, it dissolves in an alkaline solution. The fibre is worked in the solution, or “vat”. When brought out to the air, it is a bright green. Slowly the air changes it to the beautiful deep and rich blue of Indigo.

When heated from 00 to 100 C volume of a given mass of water will first decrease and then increase. If the word “ice” or “solid” is not mentioned, the word “water” means liquid water. Water vapor can be produced from the evaporation or boiling of liquid water.

Low temperature and high pressure set of conditions represents the easiest way to liquefy a gas. Liquefaction of gases is physical conversion of a gas into a liquid state (condensation). The processes are used for scientific, industrial and commercial purposes. Many gases can be put into a liquid state at normal atmospheric pressure by simple cooling; a few, such as carbon dioxide, require pressurization as well.

Details

Sound travels faster in liquids and non-porous solids than it does in air. It travels about 4.3 times as fast in water (1,484 m/s), and nearly 15 times as fast in iron (5,120 m/s), than in air at 20 degrees Celsius. Sound waves in solids are composed of compression waves (just as in gases and liquids), but also exhibit a different type of sound wave called a shear wave, which occurs only in solids.

Shortwave radio is used for broadcasting of voice and music, and long-distance communication to ships and aircraft, or to remote areas out of reach of wired communication or other radio services and that’s why it is more energetic than long waves. Shortwave radio is radio communication using the upper MF (medium frequency) and all of the HF (high frequency) portion of the radio spectrum, between 1,800–30,000 kHz.

The work done on any object goes into changing the kinetic energy of that object. Since the work done by the car engine is equal to the change in kinetic energy of the car we can say that kinetic energy is being used in performing work.

This is inertia of direction. It is the ability of body to be in a state of direction of motion .for example sun holds planets in a fixed elliptical path .this is one of the examples of inertia of direction. Inertia of direction is non-existent however inertia only apply to a body at rest or moving with a constant velocity.