Krantisinh Nana patil Vidyalaya And Junior College Bhavaninagar
Krantisinh Nana patil Vidyalaya And Junior College , Bhavaninagar Ta – Walwa Dis – Sangli Subject – English Std - VIII Teacher Name - Shrimati Pawar S. S. Optical Fibres Or Turning Light to Advantage
Optical Fibres Optical fibres were only developed after the 1950’s An optical fibre is a glass or plastic fibre. It is much, finer even than a hair and very flexible. It can be bent any way we like.
When light rays enter it at one end, they are repeatedly reflected from its sides back into the fibre by a process called total internal reflection (TIR). The rays travel in a zig-zag manner through the fibre. They can come out only fro the other tip of the fibre. Hence, the fibre can be bent or twisted or wound in any way and the light rays go wherever the fibre goes.
Wonderful things can be done by bending or ‘piping’ light in this way. Researchers at the University of Michigan first used optical fibre bundles to make a’gastroscope’ in 1956. Doctors use the gastroscope toguide light into the darkness of our stomach to find out what is wrong inside. Now –adays, ‘fibrescopes’ help doctors to look into almost all parts of our digestive tract. The gastroscope is made of two, long, thin bundles of very fine optical fibres. The two bundles together form akind of rope which is about 8 mm thick.
This rope is slowly and carefully pushed inside the patient’s body till it reaches the part that the doctor wants to examine. One bundle carries light inside the patient’s body. The other bundle carries light inside the image of the inner part to the doctor’s eyes or to a camera! Thus, using the optical fibres the doctor can ‘see’ inside the body of the patient without cutting it open!
Optical fibres have many other amazing uses. They are very useful in communications. Today, they have almost entirely replaced copper cables in telephone and computer networks. Cables of optical fibres are lighter and thinner. So, less space is needed in laying them underground. They are much, much more efficient than copper cables in carrying voice or computer data over thousands of kilometres.
The miracle of millions of people speaking to others all over the world at the same moment, the hundreds of Tv channels that we can see, the unlimited loads of data we send using the internet-none of this would have been possible without optical fibres.
But that’s not all. Optical fibres are used in many other advanced instruments’ which are required in fields like chemical and marine engineering. In some buildings, optical fibres are used to route sunlight from the roof to other parts of the building.
Optical fibres are used to light up showcases which display things made of crystal glass. A number of fibre bundles light up the glassware from different angles. Can you imagine what brilliant sight that would make?
You might have seen the beautiful fibre optic ‘light fountain’ in shop windows. Numerous glass fibres rise like a fountain from a base. There is abulb inside the base. When it is switched on, the tip of each fibre shines like a tiny spark.
If it is dark around the lamp, you might also faintly see the light ‘flowing’ through the fibres. Insome lamps, even the colour of the light changes continuously. It makes a pretty picture indeed. Optical fibres can do all kinds of things from saving life to making life beautiful.
Que. Find the meaning of the phrase ‘ turning something to your advantage’ write the two ways in which the title of the passage can be interpreted.
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