- •Lesson 1
- •The electron
- •Exercises
- •I. Answer the following questions:
- •II. Define the meanings of the suffixes in the following words and translate there words:
- •III. Read and translate the words from the text:
- •IV. Give Russian equivalents to the following groups of words of the same root:
- •XI. Translate into Russian:
- •Laboratory work I
- •Lesson 2
- •I. Memorize the following words:
- •Structure of matter
- •Exercises
- •II. Answer the following questions:
- •Двойные формы
- •Laboratory work 2
- •Lesson 3
- •The age of electricity
- •I. Answer the following questions:
- •VII. Write the following sentences in the Past and Future Indefinite Tenses. Make them negative and interrogative. Ask all possible questions (see p. 48):
- •VIII. Translate the following noun-groups:
- •Laboratory work 3
- •Lesson 4
- •Text 4 electricity
- •Exercises
- •I. Answer the following questions:
- •III. Give synonyms to the following words:
- •IV. Give antonyms to the following words:
- •V. Translate into Russian paying attention to Participle I:
- •Причастие I (Participle I)
- •Laboratory work 4
- •1. Answer the following questions:
- •2. Give three forms of the following verbs and translate them:
- •3. Make following sentences negative and interrogative:
- •4. Ask as many questions on each sentence as possible:
- •Laboratory work 5
- •Free oscillations
- •III. Define the meanings of the suffixes in the following words and translate them:
- •V. Give synonyms to the following words:
- •VI. Give antonyms to the following words:
- •VIII. Ask all possible questions on each sentence.
- •IX. Read the following passage and say what it is about:
- •Laboratory work 6
- •II. Give Russian equivalents to the following noun-groups:
- •Lesson Seven
- •1. Answer the following questions:
- •III. Define the meanings of the suffixes in the following words and translate these words:
- •IV. Give three basic forms of the verbs and translate them:
- •V. Translate into Russian paying attention to Participle II:
- •VI. Make the following sentences interrogative and give the answers:
- •VII. Ask special questions using the interrogative words in brackets:
- •VIII. Write the following sentences in the Passive Voice:
- •Participle II (Причастие прошедшего времени страдательного залога) Written translated asked
- •Laboratory work 7
- •Lesson 8
- •Text 8 Radio waves
- •Имя числительное (the Numeral)
- •Laboratory work 8
Free oscillations
Circuits with high frequency oscillations are important parts of all radio transmitters and receivers. In order to understand the operation of such oscillatory circuits we shall analyse the operation of a pendulum. If we pull such a pendulum to one side and then release it, it will oscillate. The oscillations of the pendulum are free oscillations. The movement of the pendulum from the first position to the second position and back is one complete oscillation. After the first oscillation comes the second, third etc. The movement of the pendulum from the first position to the second position does not make one complete oscillation but only half of it.
The maximum deflection of the pendulum from the zero position, i.e. distance 0-1 or 0—2 is the amplitude of oscillations.
The time necessary for the pendulum to complete one oscillation is the period.
The number of oscillations per second is the frequency. They measure the period in seconds, the frequency in cycles (cps), kilocycles (kc), and megacycles (mc).
The oscillations of the pendulum have the following properties:
They damp, i. e. their amplitude constantly decreases as a result of energy losses.
Free oscillations have harmonic character, i. e. they are sinusoidal.
The frequency of free oscillations of the pendulum depends upon its length and does not depend (is independent) of the amplitude.
As the damping process continues the amplitude of oscillations decreases but the period and frequency are constant. As the pendulum oscillates the potential mechanical energy becomes the kinetic one. In position one or two when the pendulum stops, it has the greatest potential energy, while the kinetic energy is equal to zero at that moment. As the pendulum moves from position one or two to zero, the speed of its travel and the kinetic energy (the energy of motion) increase. When the pendulum passes through the zero position its speed and the kinetic energy are the greatest, while its potential energy is equal to zero. After the zero point the pendulum speed begins to decrease and the kinetic energy begins its conversion into the potential one.
EXERCISES
I. Answer the following questions:
1. Where do we use circuits with high frequency oscillations? 2. What is it necessary to do in order to understand the operation of oscillatory circuits? 3. What oscillations has the pendulum? 4. What is one complete oscillation? 5. What is half of one complete oscillation? 6. What is the amplitude of oscillations? 7. What is the period? 8. What do we call the frequency? 9. In what units do we measure the period (frequency)? 10. What are the properties of oscillations? 11. Why does the amplitude of oscillations of the pendulum decrease? 12. Are free oscillations sinusoidal? 13. What does the frequency of oscillations of the pendulum depend upon? 14. Do the period and the frequency of oscillations change? 15. In what position is the potential energy the greatest? 16. When is the kinetic energy equal to zero? 17. When does the kinetic energy begin to convert into the potential one?