Know about lead

Lead is a Soft heavy, dull grey metal which resists corrosion well. It is a common constituent of alloys, including pewter, solder and the metal from which printing type is cast. One of the major uses of lead is in car batteries in which it forms the negative plates; the positive plates are made of a lead oxide. Another lead oxide, red lead is sometimes used as a paint pigment, as is white lead.

IR rays

Electro- magnetic waves or heat rays are called as Infra red rays. They are below the red rays of the visible spectrum and are invisible to the human eye. Infra red rays emit heat. They are used to elucidate molecular structures; and also to photograph through fog and mist or at distances invisible to the human eye. The rays are also used in medical treatments.

Mongolism

A congenital defect, also called Down’s syndrome, in which a child is mentally retarded and has slanted eyes, a broad, short face, weak muscles and stubby fingers. These children, who have a chromosome abnormality, tend to be the offspring of older mothers. Congenital heart defects sometimes occur in conjunction with this disorder-an ‘increased risk’. Mother can have a test in early pregnancy, and if positive she can be offered an abortion.

Hexadecimal Number system

The hexadecimal number system has a base of 16 having 16 digits. It is another number system that is particularly useful for human communications with the computer. Although, it is somewhat more difficult to interpret than the octal number system, it has become the most popular number system. Conversion from binary to Hexadecimal and vice versa is very easy.