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How to ? Science And Technology Question & Answer – Part 9

Science Question and Answers Riddle Part 9

In How to know, about science and technology series we will provide you information about science and technology, We are in making part of series and every part will contain 8-10 scientific questions and answer !

WHAT DOES A TRANSISTOR DO?

Electrical machines like radio and A television sets contain transistors, The transistors increase small
electric currents. They can also switch the currents on or off.

A transistor is made up of three layers of a material called a semiconductor. The thin central layer is called the base, and the two thick outer layers are the emitter
and the collector.

HOW CAN MICROCHIPS BE SO SMALL?

Inside an electronic machine, such as a calculator are microchips containing many thousands of parts like transistors. Because there are so many parts, they have to be small. The electrons that make up the current are very tiny, so the parts can be made very small too.

A tiny microchip may contain hundreds of thousands of transistors and other electronic components. This great number is necessary because the microchip has to carry out very many electronic operations very quickly to do calculations.

HOW DOES A DIGITAL WATCH WORK?

A digital watch shows the time in numbers. At the heart of the watch is a quartz crystal which vibrates an exact number of times every second. Every time it vibrates, it produces an electric signal. The other parts of the watch count the signals and change the numbers in the display to show the right time.

The quartz crystal gives out an electric signal when it is stretched or compressed. An electric current is fed from the batteries in the watch to make the crystal vibrate at an exact frequency.

HOW DOES A COMPUTER OPERATE?

To make a computer work, you have to give it a program. This tells the computer what to do to perform a particular task, like adding up. Then you give it information (data) such as numbers that it needs to start, and the computer works out the answer.

Both the program and data are held in a part of the memory unit called the RAM.

Another part of the memory unit called the ROM contains instructions that operate the central processing unit.

HOW MANY NUMBERS DO COMPUTERS USE?

Computers work by using only two numbers – 0 and 1. A computer changes numbers and words into codes made up of Os and ls. It makes calculations with these codes.

The codes of Os and is used by computers are known as binary numbers. All the program instructions and the data are fed into computers in the form of decimal numbers, letters, symbols and signs. Each of these has a particular binary number that is produced by the input unit. They consist not of figures, but of electric pulses.

HOW ARE COMPUTERS ARLE TO SPARK?

Some computers can speak to people, A They have a voice unit that can produce a certain number of words,
Each word has its own electrine code. A microchip in the computer produces the codes which go to the voice unit.

The voice unit of a computer contains a voice synthesizer. To get the words into the synthesizer, a person speaks the words into a machine that converts the sounds into digital signals. The signals are then stored in the synthesizer’s memory unit.

When the computer speaks, it takes the codes of the words required from the memory.

WHY IS NUCLEAR ENERGY SO POWERFUL?

Nuclear energy is produced by the tiny particles in the nuclei (centres) of atoms. These particles are held together by very strong forces. Breaking the nuclei releases these forces, giving great power.

In a reactor, a nuclear reaction is controlled to give useful energy. The nuclear fuel is rare form of uranium metal called uranium-235.

When the nucleus of a uranium-235 atom is struck by a neutron, it breaks into two smaller nuclei and several more neutrons.

HOW CAN ATOMS BE SPLIT?

Everything is made of tiny particles A called atoms which cannot be broken apart. If they could, everything would fall apart. However scientists can split atoms to find out about the particles inside them.

Scientists split atoms in large machines called particle accelerators. These machines use powerful electric charges to send a beam of particles along a tube. These are particles like protons that have an electric charge. The charges on the tube push or pull the particles, accelerating them to a very high speed

HOW DO WE KNOW HOW OLD FOSSILS ARE?

Fossils are the remains of prehistoric A animals and plants. They are thousands or millions of years old. A fossil, or the rock in which it is found, is very slightly radioactive. Scientists can tell how old fossils are by measuring this radioactivity.

Over a certain time, the radioactivity of a material decreases steadily to zero. It may take thousands or millions of years for a material to lose its radioactivity, Radioactivity of plants and animals begins to decrease as soon as they die. Measuring this radioactivity therefore gives their age.

WHAT MAKES SOME MATERIALS RADIO ACTIVES?

Some materials give out invisible rays called radioactivity. Some of the rays are like X-rays. Others are streams of tiny particles. They come from atoms in the material that break apart.

At the centre of every atom is a nucleus. It is made up of very small particles called protons and neutrons packed tightly together. If the material contains elements that have many protons and neutrons in the nucleus, it may be radioactive.

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