Контрольное задание №1

II. Выпишите из 4-го абзаца текста предложение, содержащее субъектный инфинитивный оборот, и переведите его письменно на русский язык.
III. Прочтите 5-й абзац текста и письменно ответьте на следующий вопрос:
What machine-tool is used for cutting?
ВАРИАНТ 5
(для студентов энергетических специальностей)
I. Прочтите и устно переведите на русский язык с 1-го по 4-й абзацы текста. Перепишите и письменно переведите 1, 2 и 3-й абзацы.
ELECTRIC MEASURING INSTRUMENTS

1. 
   Studying electric circuits requires an accurate quantitative measurement of potential or voltage, and current strength or amperage. As the electricity is forced to move along a conductor, it produces various effects such as: it sets up a magnetic field around its conductors; it produces heat; and it causes chemical changes. The magnitude of any of these effects is known to be used as a quantitative measure of the amount of current.
   
2. 
   When the current to be detected and measured is very small, one should use a galvanometer. Nowadays there are some very sensitive galvanometers which are reported to detect a current as small as 10 of an ampere per 1 mm of the scale.
   
3. 
   The basic measuring instrument which indicates any value of current strength is the ammeter. In an ammeter an armature coil rotates between the poles of a permanent magnet; the coil restrained by a spring is able to turn but through a small angle. The greater the Current in the coil, the greater the force and, therefore, the greater the angle of rotation of the armature. The deflection is measured by means of a pointer attached to the armature, the scale under the pointer reading directly in amperes.
   

4. A voltmeter is designed in order to measure the potential difference between two points in a current. Its action is similar to that of an ammeter, both of them having armatures that move when an electric current is sent through their coils.
5. However, in spite of some similarity between a voltmeter and ammeter there are also important differences. A voltmeter must have very high resistance, an ammeter, on the other hand, must have a low resistance. In actual use the ammeter is placed in series with the rest of the circuit, while the voltmeter is placed in parallel with that part of the circuit where the voltage is to be measured.