What is the SI system?

The current international standard metric system is the International System of Units (SI). Itis a system of units of measurement that uses the convenience of the number ten. It is the world's most widely used system of measurement, both in everyday commerce and in science.

The International System of Units (SI) defines seven basic units of measure. All other SI units are derived from them. These SI basic units are:

· metre for length

· kilogram for mass

· second for time

· ampere for electric current

· kelvin for temperature

· candela for luminous intensity

· mole for the amount of substance.

Electromagnetic units

Electromagnetic units are based on the magnetic properties of electric currents. The fundamental SI unit is the ampere. The units are:

1. ampere (current)

2. coulomb (charge)

3. farad (capacitance)

4. henry (inductance)

5. ohm (resistance)

6. volt (electric potential)

7. watt (power)

8. tesla (magnetic field)

9. weber (flux)

Task 1. Translate into English.

1.Электроника обычно потребляет небольшую мощность.

2. Для большинства электронных цепей ампер слишком большая единица, поэтому ток часто измеряется в миллиамперах и мощность в милливаттах.

3. Электрическая энергия преобразуется в теплоту, когда ток течет через сопротивление.

4. Если сопротивление низкое, то ток может быть очень большой.

5. Провода и кабели имеют очень низкое сопротивление и могут проводить относительно большой ток.

6. Резисторы оцениваются по максимальной мощности, которую они могут пропускать без повреждения.

7. Соотношение между током через сопротивление и рассеиваемым теплом называется законом Джоуля.

8. Международная Система Единиц (СИ) - наиболее широко используемая система измерения.

PART II

Travelling

Text 1

When you are on holiday and intend to go to the seaside or travel abroad as a tourist, you should first of all decide what means of travelling to choose. You can travel by train, by ship, by car and of course, by plane.

Travelling by plane is more comfortable, more convenient and much quicker than any other method. But not everybody likes it. Some people say they do not see very much of the country they go to. Trains are good enough for them. Some holiday-makers like travelling by sea. Of course, one can watch the sun rise and set, which is an unforgettable sight. For people who get seasick, a sea voyage is out the question. If you go by car, you may spend part of your holiday moving from place to place. You can stop wherever you like.

Whatever means of travelling you choose, it is advisable to book tickets in advance. You can book tickets yourself or do that through telephone.

Text 2

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