Kakak2 minta tolong bantuannya ya terimakasihTelevision was not invented by any one person. Nor did it spring into being overnight. It

evolved gradually, over a long period, from the ideas of many people-each one building on the

work of their predecessors. The process began in 1873, when it was accidentally discovered that

the electrical resistance of' the element selenium varied in proportion to the intensity of the light

shining on it. 'Scientists quickly recognized that this provided, away of 'transforming light

variations' into electrical" signals. Almost immediately a number of schemes were proposed for

sending pictures by wire (it was, of course, before radio).

One of the earliest of these schemes was patterned on the human eye, suggested by G. R.

Carey in 1875, it envisioned a mosaic of selenium cells on which the picture to be transmitted,

would be focused by a lens system. At the receiving end, there would be a similarly arranged

mosaic made up of electric lights. Each selenium cell would be connected by an individual wire

to the similarly placed light in the receiving mosaic. Light falling on the selenium cell would

cause the associated electric light to shine in proportion. Thus, the mosaic of lights would

reproduce the original picture. Had the necessary amplifiers and the right kind of lights been

available, this system would have worked. But it also would have required an impractical

number of connecting wires. Carey recognized this and in a second scheme, proposed to "scan"

the cells-transmitting the signal from each cell to its associated light, in turn over 3 single wire. If

this were done fast enough the retentive image to be seen as a complete picture.



9. Which of the following is the best title for the passage?

(A) The Art of Television

(B) Television in the Electronic Era

(C) Harmful Effects of Television

(D) First step in the Invention of Television.​