Complete the text with the words in the box

recharging batteries, inverter, direct current, Photovoltaic cells, charging, alternative current

 

(1) ___________________ -or solar cells – are an effective way of generating your own electricity from sunlight. The current they produce can be used immediately, may be stored in (2) _________ __________ (like the ones in cars), or can be fed into the power grid and sold to the electric company. But they produce (3)_______ _______. This is fine for (4) ___________ batteries, but is not suitable for powering household appliances, which require (5)_________ __________. For this, The DC supply from PVs and batteries needs to go through an (6)___________ - a device which converts DC to AC.

3 points

 

4.Make up the sentence from the words below:

1) long, reduces, lost, from, This, the, energy, lines, the, power, distances, over.

2) also, materials,the,on, Resistance, as, depends, conductors, used.

2 points

 

 

(This reduces the energy lost from the power lines over long distances.

Resistance also depends on the materials used as conductors.)

 

 

Test

Module 3

Term 1 Var.2

1. Complete the sentences using the correct form of the verbs in brackets. (Perfect Tenses) and translate them into Russia:

1)Ever since Volta first produced a source of continuous current, scientists (had been / have been) forming theories on this subject.

2) The temperature of hot flowing metals (have been / will have been) measured with the electric pyrometer by the time we come.

3) The physicists (had / have) discovered that treatment of water solutions with a magnetic field changes the crystal formation.

4) Under such conditions the only way to discover whether heat (had been / has been) developed is to make use of a sensitive thermometer because the heating is too negligible to be detected by other means.

4 points

2. Ask questions to the following sentence:

The study of the right contribution of gas velocity, electrical conductivity and magnetic field induction has led to the development of three approaches to the MHD power generation.

1) What …?

2) How many…?

1 points

Complete the text with the words in the box.

sine-wave, mains, hertz, alternating current, single –phase, frequency, direct current

 

Inverters convert (1) _________ __________ to (2) ___________ _____________. If an inverter is used to supply electrical appliances in a home, it must copy the supply of (3) __________ electricity produced by the generators at power stations Most inverters can produce a current which alternates precisely at the required (4) _________ - for example 50 (5) ___________ (50 cycles per second). However, not all types are able to produce a current which follows the pattern of a (6) ___________ ___________, like that of the (7) _________ ___________ AC supply used in homes. So-called “square wave inverters” only produce a very approximate copy of this wave, which can affect the functioning of many electrical appliances.

3 points

4.Make up the sentence from the words below:

1) application, and, scientists, Russian, practical, greatly, and, current, to, have, application, development, foreign, contributed, of, electric, its.)

(Russian and foreign scientists have greatly contributed to the development of electric current and its practical application.)

2) ( high, decreased, of, useful, line, The, been, due, waste, has, to, energy, voltage, greatly)

( The waste of useful energy has been greatly decreased due to high-voltage line)

2 point