TAMIL NADU STATE BOARD CLASS 12 ENGLISH 2022

Types of Books Lent: Plays (English 500, Tamil 600), Historical Novels (English 625, Tamil 641), Social Novels (English 612, Tamil 816).

One of the key factors which sustain the pace of modern life style is Telecommunication. It plays a very vital role in the commercial, industrial and economic activities of mankind and has helped to shrink the world into a global village. Exchange of information, data and facts and figures, including l

One of the key factors which sustain the pace of modern life style is Telecommunication. It plays a very vital role in the commercial, industrial and economic activities of mankind and has helped to shrink the world into a global village. Exchange of information, data and facts and figures, including live pictures from one part of the world to any other part is now routinely possible. Telegraph was the earliest means of communication between two points separated by distance. In 1876, Alexander Graham Bell discovered the telephone which made possible the transmission of human voice over long distances. In both telegraph and telephone, the transmitting and receiving points have to be connected by metal wires through which electrical signals travel in the form of current variations. The discovery of wireless at the turn of the century by Marconi was a revolution in the history of communication technology. It is no longer necessary to connect the transmitter and the receiver by wires. Instead electromagnetic waves, the existence of which was predicted by Maxwell in 1873, could be used to carry information and messages from one point to another. The advent of artificial satellites has marked a new age in the history of global communication.

The word Photography is derived from two Greek words which together mean ‘to draw by light’. Producing a photograph is simply obtaining the image of an object by the action of light on a prepared sensitive surface. Taking a photograph with a modern camera is a comparatively simple process compared with that which produced some of the early photographs, still to be seen, for instance, in family albums. The early camera was large and cumbersome to handle, and, when assembled in position, had to be carefully focussed on the object - a lengthy operation. Later on, with focussing scales on cameras (and built-in range finders on the more expensive models), the setting occupied only a few seconds. With the early hand - operated cameras the exposure was made by removing a lens cover, and counting the length of the exposure in seconds. There was also the tedious task of loading and of preparing a sensitive glass for which the photographer had to carry with him a portable dark room or a large plate changing box. Now the same operation consists simply of breaking the seal on a carton and loading, in daylight, a roll of film, which provides sufficient and light sensitive material for eight to thirty six exposures according to the type of camera used.

of an object by the action of light on a prepared sensitive surface. Taking a photograph with a modern camera is a comparatively simple process compared with that which produced some of the early photographs, still to be seen, for instance, in family albums. The early camer a was large and cumbersome to handle, and, when assembled in position, had to be carefully focussed on the object - a lengthy operation. Later on, with focussing scales on cameras (and built-in range finders on the more expensive models), the setting occupied only a few seconds. With the early hand - operated cameras the exposure was made by removing a lens cover, and counting the length of the exposure in seconds. There was also the tedious task of loading and of preparing a sensitive glass for which the photographer had to carry with him a portable dark room or a large plate changing box. Now the same operation consists simply of breaking the seal on a carton and loading, in daylight, a roll of film, which provides sufficient and light sensitive material for eight to thirty six exposures according to the type of camera used.