- •Part I
- •Text. Physics and physical phenomena
- •Laboratory Exercises
- •Additional Material
- •M. V.Lomonosov
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Measurement of Volume
- •Text. The metric system
- •Dimensions of a Solid Body
- •Laboratory Exercises
- •Additional Material
- •Origin of the Metric System
- •Text. The kinetic theory and the three states of matter
- •3 Not to matter — не иметь значения will make full use — займут
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Text. Mass and weight
- •3. Much, more, the most; little, less, the least; good, bet ter,
- •4, .,. Er than, more ... Than
- •5. At, on, over .., etc.
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Text, force, work, energy and power
- •Exercises
- •Additional Material
- •1. Have supported, has altered....
- •2. Energy can be converted...
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Isaac Newton
- •Text. Heat
- •1. Heat is known to be a form of energy.
- •2. You place, you placed, you have placed. They take, they took, they have taken.
- •3. Newton began to think about heat.
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Text. Transmission of heat
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Good and Bad Conductors of Heat
- •Text. Calorimeters
- •1. It is usual to transfer ...
- •2. There is; is there; there is no ...
- •3. The setting up of ...; the reading of ...
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Text. Wave motion and sound
- •1. It does not move forward but returns again...
- •2. It is evident, it is clear.
- •Exercises
- •Additional Material
- •Text. Light
- •1. It becomes red-hot, it is the reason, it was cold...
- •2. High temperature produced by..., in a substance called... . Exercises
- •Laboratory Exercises
- •Additional Material
- •Text. Reflection and refraction of light
- •1. Do bodies emit? Does he make? Did it represent?
- •2. Have they shown? Had he travelled? Was it reflected? Is he going? Exercises
- •Laboratory Exercises
- •Additional Material
- •Text. Lenses
- •1. After leaving the lens...
- •Exercises
- •Additional Material
- •Text. Simple cell
- •1. The twitching of; the reading of...
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Voltaic Cells
- •Text. The accumulator
- •1. A plate containing, a plate being immersed...
- •2. Achieved by connecting; determined by testing...
- •Exercises
- •Additional Material
- •Text. Principle of electric motor
- •1. They are used to pull...
- •2. When viewed, while doing...
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Electric Bell Circuit
- •Text. Moving-coil ammeter and voltmeter
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Moving-Coil Galvanometer
- •Text. Electromotive force
Laboratory Exercises
8. Listen and read the following word combinations:
reflection and refraction of light, sources of light, particular direction, a homogeneous medium, silvered surface, passes through, point of incidence, angle of incidence, laws of reflection.
9. Listen and repeat in pauses:
The sun is a self-luminous body which emits light of its own. Common bodies around us are not self-luminous. These bodies vibrate as they reflect in all directions the light which falls on them from the sun. When a beam of light, travelling in a homogeneous medium, comes to a second medium, some of the light is reflected. The incident ray is the direction in which light falls on to the reflecting surface. The bending of the ray of light when passing from one medium to another is known as refraction.
10. Listen to these questions on the above text and answer them:
1. What bodies are not self-luminous? 2. What bodies are self-luminous? 3. When is any of the light reflected? 4.What is the incident ray? 5. What is known as refraction?
11. Ask questions using the model.
Model: The sun is known to be a self-luminous body.
What is the sun known to be?
1. Common bodies around us are known to be not self-luminous. 2. Polished surfaces are known to reflect light. 3. The angle of incidence is found to be equal to the angle of reflection.
12. Listen to this short dialogue and learn it by heart:
- Will you kindly tell me details about light. What is a light ray?
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— It is the direction along which light propagates. Do you know what the angle of incidence is?
-- Yes, I do. The angle of incidence is the angle formed by the incident ray and the perpendicular. But what is the incident ray?
— It is the ray that falls on to the reflecting surface. What angle is called the reflected one?
— The angle formed by the same perpendicular and the reflected ray. What is the reflected ray?
— It is the ray which is reflected by the reflecting surface.
13. Suggested topics for oral narration:
1. What is meant by self-luminous and not self-luminous bodies? How are they related to each other?2. Define reflection and refraction of light.
Additional Material
Read the text, get its central idea. What does the colour of light
depend on?
The Colour of Light
Since light of different colour has different refrangibility, light is scattered or dispersed by refracting media. Dispersal from rain-drops produces the rainbow. The dispersion of light by lenses which produce a colour-fringed image may be remedied by the use of achromatic lenses. Colour is analogous to pitch; it depends upon the length of the light waves, or upon the frequency of vibration. The colour of an opaque object depends upon the colour of the light it receives and upon the colour of the light it can reflect. Any two colours that combine to produce white light are complementary.
Incandescent solids, liquids, and compressed gases yield continuous spectra; luminous gases produce bright-line spectra. Gases absorb light waves of the same length they would emit if heated to luminosity.
Read the text and describe the critical angle:
Critical Angle
When a ray of light passes from a dense medium such as water to a rare medium such as air, it is bent away from the normal so that the angle
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of refraction is greater than the angle of incidence. If the angle of incidence is made larger and larger the angle of reflection will also become larger and larger and will always be greater than the corresponding angle of incidence. When the angle of incidence is increased sufficiently, the angle of refraction becomes 90 deg, and the refracted ray travels along the surface of separation between the two media. That angle of incidence for which the angle of refraction is 90 deg is called the critical angle.
UNIT 14