сделать два задания The conducting materials give green light to electrons which move from one atom to another when the potential difference is applied across them. This flow of electrons in a closed circuit is called current. On the basis of the direction of movement of electrons in a closed circuit, the electric current is mainly classified into two types, i.e., the alternating current and the direct current.
The current which changes its direction at a regular interval of time such type of current is called alternating current. Direct current is unidirectional or flows only in one direction.
The charges in the alternating current flow either by rotating a coil in the magnetic field or by rotating a magnetic field within a stationary coil. In direct current, the charges flow by keeping the constant magnetism along the wire.
The frequency of the alternating current give or take 50 to 60 hertz depends on the country standard, whereas the frequency of the direct current always remains zero.
The power factor of the alternating current lies between zero to one, whereas the power factor of the direct current always remains one.
The alternating current can be graphically represented through different irregular wave shape such as triangular wave, square wave, periodic wave, the saw-tooth wave, sine wave, etc. The direct current is graphically represented by the straight line.
The alternating current transmits over a long distance with some losses, whereas the direct current transmits over very long distances with negligible losses.
The alternating current is converted into direct current with the help of rectifier whereas the direct current is converted into alternating current with the help of the inverter.
Few substations require for the generation and transmission of the alternating current. Extra substations require for the transmission of direct current.
The alternating current is used in industries, factories, and for the household purposes. The direct current is mainly used in electronic equipment, flash lighting, hybrid vehicles, electroplating, electrolysis, for exciting the field winding of the rotor, etc.
1. Выпишите из текста предложения, содержащие герундий / герундиальный оборот.
2. Найдите в тексте английские идиомы, выпишите и переведите их.
Объяснение:
1. Where were you going yesterday evening? - I was going to the railway station to meet my uncle.
2. Where was your sister shopping yesterday morning? - Well, she was shopping in a new shopping centre all day yesterday.
3. How long were they preparing for the test last Sunday? - They were preparing for the test from 2 to 6 o'clock.
4. What book was he reading at five o'clock yesterday? - He wasn't reading. He was translating a short story for his French lesson.
5. What was Nick doing yesterday evening? - He was playing a new computer game all the evening.
Подробнее - на -
1 We will have been decorating our house by Friday.
2 By the time my granny retires,she will have been working as a teacher for thirty years.
3 Ben will have been running his own business for seven years by the next month.
4 He will have been building his own house by the end of this year.
5 By 10 o'clock they will have been sleeping for eleven hours.
6 By Christmas Ann will have been working as a model for three years.
7 By the time she arrives in London,she will have been travelling four eight hours.
8 By 4 o"clock I will have been waiting for a bus for two hours.
9 Sam's parents will have been living in the country for twelve years by the time his mother is sixty.
10 By the time I finish school I will have been writing many English exercises.