- •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
10. Listen and read the following word combinations:
the nature of light, sources of light, two schools of thought, tiny particles, straight lines, the whole of space, behaviour of light, miles per second, thin tungsten wire, ordinary electric lamp, the bombardment of gas molecules, a discharge lamp tube, invisible radiation.
11. Listen and repeat in pauses:
Light is a form of radiant energy, just as is the heat radiation. But light is a special form of radiant energy that can cause the sensation of light. Light, in common with the other forms of electromagnetic radiation, is given out in the form of waves. Light spreads in every direction. The waves which cause the sensation of light are very tiny indeed. At present light is supposed to consist of streams of tiny wave-like packets of energy called "quanta". Atoms emit light at the high temperatures produced by different kinds of energy. The sun is the chief source of light and heat.
12. Listen to these questions on the above text and answer them:
1. What is light? 2. What can light cause? 3. What is light supposed to consist of? 4. When do atoms emit light?
13. Ask questions using the model.
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Model : When light strikes matter, there can be three possible effects.
When can there be three possible effects?
1. When the temperature of a body is raised, the body emits invisible radiation. 2. When a body becomes red-hot, visible radiations begin to be emitted. 3. When tungsten is surrounded by nitrogen it can be heated to a high temperature.
14. Suggested topics for oral narration:
1. What is light? How do we see objects?
2. Tell about natural and artificial sources of light.
Additional Material
1.Read the text and get its central idea. Give the physical difference between light and sound waves:
Difference Between Light and Sound Waves
We are now in a position to distinguish fully between light and sound waves. The physical difference, of course, is that light waves are due to varying electric and magnetic forces, while sound waves are due to vibrating layers or particles of the medium concerned. Light can travel through a vacuum, but sound cannot travel through a vacuum. Another very important difference is that the vibrations of the particles in sound waves are in the same direction as that along which the sound travels, whereas the vibrations in light waves are perpendicular to the direction along which the light travels. Sound waves are therefore longitudinal waves, whereas light waves are transverse waves. As we have seen, sound waves can be reflected and refracted, and can give rise to interference phenomena; but no polarization phenomena can be obtained with sound waves since they are longitudinal waves, unlike the case of light waves.
2. Read the text and speak of the time light travels from the sun to the earth:
Velocity of Light. Light is an electromagnetic wave motion. It travels through empty space, as well as through transparent substances as air, glass and water. Its velocity, which is 186,000 miles per sec, is so great that in 1 sec. it would travel more than seven times around the earth at the
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equator. Light travels from the sun to the earth in a little over 8 min., but it requires 4 years for light to travel from the nearest star to the earth.
3. Read this text and describe a simple experiment which reveals how light travels:
Light Travels in Straight Lines. Under ordinary circum-stances light travels in straight lines and does not appreciable bend around objects. A simple experiment which reveals how light travels can be performed with three cardboard or metal screens having small holes in their centres These are adjusted so that the holes are in a straight line by threading a string through the holes and putting it taut. The light from a candle flame placed at A can then be seen through the holes by an eye at B. If, however, one of the screens is moved so that the holes are no longer a straight line, the light is cut off. We therefore conclude that light travels in straight lines.
UNIT 13