1. Fresh Assignments
Assignment I
Practice 1
Change the following sentences into passive form
1. We examine the mixture under a microscope.
2. We can see several particles of iron and sulphur.
3. We use the name quick lime for calcium oxide.
4. We should place the metal on a dry surface to cut it.
5. We form some salts from hydrochloric acid.
Practice 2
Complete the following by using appropriate form of the verbs.
Apply, use, fracture, emit, stop, crack, see, discover.
X-rays are electromagnetic waves with very short wave lengths. They are ----- when
fast-moving electrons are ------- suddenly. Very soon after they were ----,
X-rays were ------ in order to take pictures of bones that have been ------ or -----.Solid
bones stop X-rays from passing through it and are --------- as opaque image in the X-ray
film. X-rays are thus an example of how a discovery in basic science can be -------- for
solving practical problems and becomes technologically useful.
Practice 3
Replace the underlined words and phrases by using formal and scientific words.
Negatively charged particles, positively charged particles, carrying, equal, maintain, composed,
types, named, properties, occupies, valance, configuration, defines, informs.
The atom is made up of at least two kinds of particles, those having positive electric charge.
Moreover, the number of positive and negative charges must be same in order to keep the atom
as electrically neutral. The particles, which are having negative charge, were given the name
electrons and the particles having positive charge were called protons. The position that an
element has in the periodic table tells its electronic arrangement. The electronic arrangement
tells us how many shells of electron it has. The group, the atom I in, tells us the number of
electrons in its outermost shell. This number defines many qualities of the atom such as
valance. Metallic character, the size of atom and so on.

2. Techniques of precision
Scientific writing is not only factual and objective, it is also precise and to the point. The
various techniques that could be used to make a passage precise include:
• Avoiding repetition or restatement
• Separating essential from non-essential points
• Separating details and supporting points from main ideas
• Using appropriate transitional and linking devices
• Logically organizing information
• Using appropriate grammatical features
• Using appropriate words and phrases
• Avoiding wordiness
• Ensuring unity and coherence in writing
(1) Digital computers are really counting machines. You choose them for high-speed
mathematical calculations. You can multiply, divide, add, or subtract numbers with
them. You can operate the smaller ones manually like typewriters. You
programme larger digital computers with punched cards, punched tape or magnetic
tape.
Practice 4
Rewrite the following passages formally and objectively using impersonal passive and
other devices:
1. We know that elements are things, which have only one kind of atoms. Hydrogen,
oxygen, silver, copper are examples of elements. There also thing made of more
than one kind of atoms combined together. We call these substances compounds.
Water is made of hydrogen and oxygen; and common salt is made of sodium and
chlorine.
2. We see that when we apply force on an object, the velocity of the object changes,
that is, it accelerates the object. The resistance to this change in velocity depends on
the mass of the object. That means that we can change the velocity of lighter objects
more easily than we can change the velocity of heavier bodies.
3. An ionic compound is a collection of an equal number of positive and negative ions
kept in a three dimensional lattice. We can dissociate ionic compounds into their
constituent ions with little effort. Further, we can electrolyze ion compounds to
produce elements or covalent molecules of the respective atoms.
4. We know that chemical reactions involve the breaking of bonds and the making of
new ones. We often need to supply energy to get the reaction going. The energy that
we supply may be in the form of heat, light or mechanical shaking for proper
contact between the reactant molecules and electricity. When chemical reactions
occur, we can notice a great variety of rearrangements of atoms.

3. I.
22
i
II. We know that a layer of air surrounds the Earth. This is
; between 150 and 200 km thick and we call it the
atmosphere. Air is invisible and therefore we can not see
it. But it takes space and has weight in the same manner
visible things do. The atmosphere weighs down on the
surface of the Earth. We can not feel this weight pressing
on us because air not only exerts a downward pressure,
but it also exerts pressure upwards and sideways, and the
equal pressure, which our blood exerts in every
direction, balances this pressure.
! III. An acid is a compound containing hydrogen, which we
' can replace, directly or indirectly, by a metal. We can
. classify acids into two groups. There are acids which
always contain the element carbon. We call them organic , acids. They often
come from growing things, like fruit.
' We have two kinds of organic acids, citric acid and
acetic acid. We find citric acid in lemons and oranges , and other citrus
fruits. We find acetic acid in vinegar.
Inorganic acids are those acids, which do not contain the
element carbon.
2. Read the following passages and fill in the blanks with
appropriate connectives/ linkers/ transitional devices:
I. Substances consist of small parts, or particles, ---1--- are

4. known as molecules. Molecules are composed of atoms.
Some substances, ---2--- salt and waLer, have molecules -
--3--- can be analysed further into other substances. ---4
-- a molecule of water is analysed, ---5--- , it will be
found to consist of two atoms of hydrogen ---6--- one
atom of oxygen. Hydrogen and oxygen, ---7--- , are
elements. ---8--- if a molecule of oxygen is analysed it
will be found to consist of only atoms of oxygen ---9--
not of any other substance.
23
II. Air is invisible and ---1--- it can not be seen. ---2--- it occupies space ---3--- has weight.
The atmosphere, ---4-- , weighs down on the surface of the Earth. ---5---, this weight can
not be felt pressing on us ---6--- air not only exerts a downward pressure, ---7--- it also exerts
pressure upwards ---8--- sideways, ---9--- this pressure is balanced by the equal pressure ---
10--- our blood exerts in every direction.
3. The following sentences go together to form two short paragraphs, but they are in the
wrong order. Keeping in mind the topic sentence, put them in the right order:
A. Then the cap is screwed back in place with about 3 mm of
the wick protruding through the hole in the cap.
B. The container is made of glass or metal.
C. A spirit burner is a device, which is used to provide a source
of heat for laboratory work.
D. To extinguish the flame, the evaporation cover is simply placed over it.
E. To use the burner, the cap is unscrewed and the container
filled about three-quarter full with methanol.
F. It consists of a container, a metal cap with a hole in it, cotton
or nylon wick, and an evaporation cover.

5. Assignment II
Practice 1
Fill in the blanks with appropriate connectives:
1. ------- the velocity of a body changes with time we say that the body is accelerating.
This change could be a change in its speed or direction of motion or both. Motion in
a circle at constant speed is, ------, an example of accelerated motion. --------- the
speed may not change, the direction of motion changes constantly.
2. Over one hundred elements are known today. Most of them take part in a variety of
chemical reactions. ------ the total number of chemical substances in the world must
be many millions. ------- all these have to be made, using the hundred odd elements
as building blocks. One would, ---- need to understand the rules ------ the patterns of
how these elements react ---- the basis of their properties.
3. An ionic compound is a collection of an equal number of positive ----- negative ions
arranged in a three dimensional lattice. Ionic compounds can be dissociated into
their constituent ions with little effort. ----, they can be electrolyzed to produce
elements or covalent molecules of the constituent atoms. -----, NaCL upon melting
or upon dissolving in water produces Na+ and CL – ions. Electrolysis of molten
NaCL give Na and CL2 water also weakens the attraction between the ions in an
ionic compound. ----- many ionic compounds dissolve well in water. ----, ionic
compounds can conduct electricity. Most ionic compounds are made of metals.
-----, covalent bonds have quite different properties. They do not ionize or conduct
electricity. Electrolysis of covalent bonds is --- not possible. Many covalent bonds
are not soluble in water. Covalent bonds dissolve much easier in organic liquids.
---- the bonding here is by electron sharing ---- by electron attraction, the number
of atoms in covalent molecules is not indefinitely large. They have lower melting
----- boiling points than ionic compounds. Many covalent molecules are in the gas
phase or liquid state (CL2, H2O).

6. Practice 2
Read the following paragraphs, and identify the topic sentences
1. Matter refers to anything that has weight and occupies space. Matter may exist
in three states: solid, liquid and gas. All substances, except those which
decompose on heating, like wood, may be changed from one state to another. A
substance in the solid state may be changed into a liquid substance, and one in
the liquid state may be changed into a gaseous state. Changes can take place in
reverse order as well: gases may be changed into liquids and liquids into solids.
A solid substance such as ice may be changed into the liquid state, liquefied, to
become water; and this may be changed into the gaseous state, or evaporates, to
become steam. Steam may also be converted into water and water into ice.
2. Crude oil is a mixture of different compounds that boil at different temperatures.
The lightest fraction consists of gases that boil below atmospheric temperature.
The next fraction, normally refined into gasoline, boils between at 30o C and
2000C is termed kerosene. The fraction boiling above about 320 0 C is commonly
refined into heating diesel and lubricating oils. The remaining and heaviest
fraction is the residue, which supplies waxes, asphalts and some fuel oils.
3. A telescope is an optional instrument used for magnifying distant objects. It
consists of two essential parts: the objective and the eye-piece. The forms a real,
diminished-in-size and inverted image of a distant object at its focus. The
position of the eye-piece is so adjusted that this image is formed between the
optional center of the eye-piece and its focus. The eye-piece then forms the final
image, which is virtual, enlarged and erect.
Practice 3
Read the following passages and fill in the blanks with appropriate
connectives/linkers/transitional devices:
1. Substances consist of small parts, or particles, ------- are known as molecules.
Molecules are composed of atoms. Some substances, ----- salt and water, have
molecules----- can be analyzed further into other substances. ---- a molecule of
water is analyzed, ------, it will be found to consist of two atom of hydrogen ----
one atom of oxygen. Hydrogen and oxygen, ----, are elements. ---- it a molecule
of oxygen is analyzed it will be found to consist of only atoms of oxygen-----
not of any other substance.
2. Air is invisible and ---- it cannot be seen. ---- it occupies space---- has weight.
The atmosphere, ----, weighs down on the surface of the Earth. ----, this weight
cannot be felt pressing on us ---- air not only exerts a downward pressure, ---- it
also exerts pressure upwards --- sideways, ---- this pressure is balanced by the
equal pressure ---- our blood exerts in every direction.

7. Practice 4
The following sentences go together to form two short paragraphs, but they are in
the wrong order. Keeping in view the topic sentence put them in the right order:
1. Then the cap is screwed back in place with about 3mm of the wick protruding
through the hole in the cap.
2. The container is made of glass or metal.
3. A spirit burner is a device, which is used to provide a source of heat. For
laboratory work.
4. To extinguish the flame, the evaporation cover is simply placed over it.
5. To use the burner, the cap is unscrewed and the container filled about three-
quarter full with methanol.
6. It consists of a container, a metal cap with hole in it, cotton or nylon wick, and
an evaporation cover.
Practice 5
Read the following information in note form about carbon. Use these as set of
notes in order to write a description of carbon.
• Diamond and graphite
• Pure crystalline form
• Combined form as a constituent of all organic materials
• Inorganic compounds
• Solid non-metallic chemical element
• Soft black substance
• Used to drill or shape glass and ceramic articles and to grind and polish steels
• Hardest known substance
• Industrial diamond.

8. Assignment III
Practice 1
Read the description of a computer and complete the following table:
A computer is an electronic data processing device, which has memory to store
data, ability to process data into meaningful information and ability to perform fast
and accurate calculations. It consists of input devices, output devices and a Central
Processing Unit (CPU). The input devices, which include keyboard and floppy disk
drives, convert information to data and send it to CPU for further processing. The
output devices comprise if Visual Display Unit (VDU) and printers. The
information that has been entered by the user using input devices can be viewed on
the VDU. Printers are used to get the output from the computer. The CPU contains
the control unit, the memory unit and the arithmetic/logic unit. The information/
data is received by the control unit and is sent to the memory unit for storing.
Finally, the control unit is sent to the memory unit for storing. Finally the control
unit sends the data from the memory unit to the arithmetic/logic.
Components of a computer Functions of each component
Input devices -------------------------------------
-------------------------------------------- Displays data
Central processing unit ----------------------------------------
Printer ----------------------------------------
--------------------------------------------- Receives data from the input devices
Memory unit ----------------------------------------------
Practice 2
Read the following description and identify the words and expressions that denote
structure/function and make a table:
An Electronic Watch

9. An Electronic Watch is a device for showing time. It consists of a quartz crystal and a
tiny integrated circuit. An electronic current from a battery makes the quartz crystal
vibrate. The integrated circuit contains hundred of electronic components. It turns the
vibrations into pulse for every second. Then it stores the seconds to make minutes,
hours and days.
Practice 3
Read the following sentences of a paragraph and identify the main aspect
expressed in each sentence:
A. Two pieces of platinum foil are connected to a battery.
B. One piece is connected to the positive terminal and the other to the negative.
C. They are then placed in blue copper sulphate solution contained in a beaker.
D. A test-tube is filled with the solution and fixed over the anode.
E. When the current is switched on, it passes from the anode to the cathode through
the solution.
F. It will be seen that the blue solution of copper sulphate gradually becomes paler as
the current passes through it.
G. At the same time, gas is given off from the anode and is collected in the test tube.
Practice 4
Use the following table to write a paragraph or two on the fractionation of
petroleum:
Fraction Boiling Uses
Range(K)
Gaseous 113-303 Gaseous fuel, production of
hydrocarbons carbon,hydrogen,gasoline
Petroleum ether 303-363 Solvent (used in dry-cleaning)
Gasoline 343-473 Motor fuel
Kerosene 448-548 Illuminant, fuel ( domestic and for jet
engines
Gas oil, fuel oil and 523-673 Furnace fuel, fuel for diesel engines,
diesel oil cracking
Lubricating oils, 623 and up Lubrication
greases
Paraffin ( wax) Melts Candles, water proofing, fabrics
325-330

10. Petroleum coke Residue Artificial asphalt, fuel, electrodes
Practice 5
Present the process of photosynthesis as a flow diagram
Assignment IV
Practice 1
1. Read the following set of instruction and identify purpose and method:
A. Connect a battery of four dry cells each of 1.5 volt with an ammeter, leaving a gap
in the circuit. Complete the circuit by connecting in the gap one after the other a
torch bulb, a 15 watt bulb, a thick strip of copper and a piece of nicrome wire.
B. Use a nichrome or eureka ire of about 50-cm length in order to study the variation
of electric current.
C. Use an immersion heating rid of 2 KW and 220 volt rating to heat a bucket
containing 15 lts of water.
D. Place the microphone on a table. Adjust the recording level by means of recording
level control. Do not allow the needle to reach the coloured area. The microphone I
equipped with a remote control. To stop the tape, move the switch forwards. To
start, move the switch backwards.
2. Study the following pieces of information in two sets in the table. Then write
instructions by combining the two sets in a logical manner (Purpose/method).
Use appropriate sequence words if.
Set up the circuit The lines of force are drawn
Use the rheostat As shown in the figure
Place the compass needle in various Interchanging the connections of the
positions on the cardboard around the battery
wire
Mark the directions of the north pole Allow a current of 2 ampere through
the circuit from the car battery
Reverse the current directions ---------------------------------------

11. Practice 2
1. Change the following sets of informal instructions into formal instructions:
• In order to understand force and its relation to motion, you should try a simple
experiment. You should place a rubber ball on a flat table. If you do not disturb the
ball, it will continue to remain where it was placed. You will notice that its sped is
zero. Its acceleration will also be zero. Now, you should give the ball a slight push.
You will find that it starts moving with some speed. You should measure this peed
by using a ruler and a stop watch or a watch with second hands.
• You should take two coins and place them next to each other on edge of the table.
Now you should flick away one of the coins parallel to the ground and release the
second so that it just topples over. You should take care to ensure that both coins
leave the table at the same time. You should decide whether the two coins hit the
ground simultaneously by listening to the click of the coins as they reach the
ground.
Practice 3
1. Change the following sets of instructions into descriptions:
• Take torchlight, transparent glass sheets, and plastic sheets or paper of red or
green colour. These kinds will produce green and red light when you lit the torch
behind them. First, produce red light and place a red object in the path. It will
appear red. Now produce green light and illuminate it on the same red object. The
object will now appear black. Finally, examine a blue coloured object in green
light, and in red light. You will notice that it appears black in both the cases.
• Take three torches. Cover the glass of one with red cellophane paper, another with
blue and the third with green. Set up the torches in the darkened room so that their
beams overlap. Now project all three coloured lights on a screen or a wall. You
will see the colour overlap and produce new shades.
• Fill an open mouthed bottle with a saturated solution of iodine in aqueous KI.
Place some powdered but weighed quantity of solid iodine in a spoon attached
with a wire passing through a cork. Inert the spoon into the bottle and hold it
under the iodine solution. Keep the bottle aside for a few hours.
2. Change the following sets of instructions into informal and formal instructions:
:
• Take some filaments of algae spirogyra on a glass slide. Put a drop of water,
cover the slide, and observe it under the microscope. Now irrigate the slide with a
salt solution and note the changes in the cells of the filament. Now irrigate the
slide with water and observe the change.
• Observe different kinds of plants and animals in the area. Record and find the
number of populations of these organisms. Categorize them into plants and animal

12. populations. Further, categories the list into populations of birds, reptiles and
mammals.
• Fill an open mouthed bottle with a saturated solution of iodine in aqueous KI.
Place some powdered but weighed quantity of solid iodine in a spoon attached
with a wire passing through a cork. Inert the spoon into the bottle and hold it
under the iodine solution. Keep the bottle aside for a few hours.
• First take a piece of balsa wood and cut out the shape of a fuselage. For the wings
and tail plane use stiff wood. Cut the fuselage carefully in order to attach the tail
plane without glue. Attach matchsticks to the fuselage to support the wings. Cut
out the wings. Use elastic bags to extend the wings to the fuselage at an angle of
15 degrees. Finally, in order to help balance the plane to flight, fix the lead weight
on the plane ‘nose’.
3. Combine the following statements logically to write a set of instructions for
making alloys:
• The other ingredient is melted.
• It is allowed to solidify.
• The two metals, which are the ingredients of the alloy, are melted.
• The main ingredient is melted.
• The other ingredient dissolves.
• The other ingredient is added to it.
• The mixture is poured into metal or sand moulds.

13. Assignment V
PRACTICE 1
The following sentences can form a meaningful paragraph based on deductive generalization,
but they are not in order. Arrange them in the correct sequence:
A. These are usually referred to as conductors.
B. Often some parts or components of the circuit are intentionally designed to offer high
resistance.
C. The resistance of a material plays an important role in electric circuits.
D. A substance that has infinitely high resistance will not allow electricity to flow through.
E. The parts or components of the circuit, which are to provide a path for the movement of charges,
are made from materials with low resistance.
F. These are made from materials with a high resistance which are called resistors.
G. It is called an insulator
PRACTICE 2
Study the following table and write short paragraphs matching each specific statement to its
corresponding generalization. Use appropriate connectives.
Specific Statements Generalizations
Uranium is essential as a source of Elements are substances made of
Water is made
radioactivity. of hydrogen and oxygen; Most
only materials in nature are
carbon dioxide is made of carbon and mixtures of elements and comp-
oxygen; sugar is made of carbon, oxygen ounds in various proportions.
and hydrogen; and common salt is made of
sodium and chlorine.
An aero plane flying at a height has both Some rare materials have highly
potential specialized uses.
and is a mixture of elements such as oxygen, There are substances made of
Air kinetic energy.
nitrogen, argon and compounds such as more than one kind of atoms
carbon combined together.
Hydrogen gas is composed of atoms of An object can have both potential
hydrogen, and oxygen gas is composed of and kinetic energy.
atoms of oxygen.

14. PRACTICE 3
Study the following information about magnets:
• The North Pole of one magnet is brought close to the South Pole of another magnet.
• The north poles of two freely suspended magnets are brought into proximity.
• The ends of the two magnets will swing away from each other.
• The two ends will attract each other.
• A North Pole will attract a South Pole.
• A North Pole will repel a North Pole.
• A North Pole will be attracted by a South Pole.
• A North Pole will be repelled by a North Pole.
Now write a short paragraph using the information and arranging it in inductive order.
Write an appropriate generalization for the paragraph.

15. Assignment VI
PRACTICE 1
Change the following real definitions into nominal definitions:
a) Mineral hardness is defined as its resistance to thee mechanical disintegration, which
takes place under the action of a stronger body.
b) Luminescence is the basis of modern illumination techniques, which utilize the
fluorescence of inorganic compounds.
c) A trace is a substance used to follow a chemical reaction or a physical process.
d) A neutron is a particle having the same mass as a proton but carrying no electrical
charge.
e) A catalyst is a substance, which accelerates a chemical reacting.
PRACTICE 2
Complete the following definitions:
a) Ecology is the -------------------------------- in relation to, their environment.
b) Hydrometallurgy can be defined as the ------------ of ------------------------ at ordinary
temperature by leachi8ng ore with liquids.
c) Metallography is --------------------------------------------------------------------- of metals
and alloys.
d) Dynometer ---------------------------------------------------------- the electrical power.
e) An optical device ------------------------------------------ and solidity is stereoscope.
f) Thermostat is an ---------------------------- which is used ----------------------------.
PRACTICE 3
Rewrite the following definitions as generalizations:
a) A computer is an electronic device which can store large amount of data and instructions.
b) A laser is a very special source of light which generates optical radiation utilizing a
process called stimulated emission.
c) A hydrophone is an instrument used for measuring sound under water.
d) A radio micrometer is an instrument used to measure heat radiations.

16. e) Local Area Network (LAN) is a local configuration of computer networks sharing
information and computer resources.
PRACTICE 4
Read the following expanded definition and write the structure of the paragraph:
The energy transmitted from one body to another in the form of rays or radiations is called
radiant energy. Cosmic rays, garnma rays, X-rays, ultra-violet rays, visible rays, infra-red
rays, radio waves and heat are the examples of radiant energy. These waves are
associated with electric as well as magnetic fields. Thus, these radiations are called
electromagnetic radiations.
PRACTICE 5
Expand each of the following definitions in a short paragraph:
I. An element is a substance that is made of only one type of atoms.
II A decomposition reaction can be defined as a chemical reaction in which a
molecule is broken down into smaller parts.
III Quantities which need both magnitude and direction for
their complete description are called "vectors".
IV The momentum of an object is the product of its mass
and velocity.
V The ability to do work is called energy.
Assignment VII

17. PRACTICE 1
Analyze the following items and classify them into different levels of generality:
• Elements, substances, sugar, hydrogen, salt, compounds, water, carbon dioxide,
copper, silver
• Plastics, bronze, metals, copper, engineering materials, steel, non-ferrous metals,
thermosets, thermoplastics, non-metals, ferrous metals, brass, iron, ceramics
• Ionic compounds, sodium chloride, covalent compounds, methane, ammonia,
compounds
• Nickel-iron storage cells, dry cell, storage cells, silver cells, nickel-cadmium
storage cells, cells, lithium cells
• Iron, calcium, cell-building food, organic foods, phosphorus, inorganic foods, food
substances, energy-producing food. Fats, carbohydrates
PRACTICE 2
Rewrite the following classificatory descriptions according to specific to general
organization:
l. Deserts are classified into three categories, Tropical (hot), Mid-latitude (Temperate)
and High-latitude (Polar/cold). Sahara, Arabian and Thar deserts are tropical whereas
Gobi, Great Basin (US), and Turkistan deserts are mid-latitude deserts. Antarctica is a
high-latitude desert.
2. Islands are broadly divided into four types, continental, oceanic, tectonic and coral.
Continental islands are those islands that rise from the continental shelf, like the
British Isles or Newfoundland. Oceanic islands are those that arise from the bosom of
the oceans. Ascension, for example, rise from the Central Atlantic ridge (mountain).
Tectonic islands are created by movements in the Earth's crust. Barbados in the West

18. Indies and Kodiak Island near Alaska were formed this way. Coral islands are the work
of minute sea organisms called coral polyps.
3. The nutrients found in foodstuffs may broadly be classified into two categories, macro
nutrients and micro nutrients. Proteins, fats and carbohydrates are called macro
nutrients whereas vitamins and minerals comprise micro nutrients. Carbohydrates and
fats are energy producing nutrients and proteins are as cell-building nutrients.
4. Vitamins can be broadly divided into two groups, fat- soluble and water- soluble
vitamin. Vitamin A, D, E and K are fat soluble vitamins, while vitamin C and B are water
soluble vitamins. Vitamin B includes vitamins B1, B2 and other B group Vitamins
PRACTICE 3
Analyze the following items and classify them in a tree diagram:
1. Honey, raw cane sugar, processed sugar, glucose, natural sugar, white sugar, soft brown
sugar, fructose, sugars
2. Iron, carbohydrates, organic food, inorganic food, proteins, cell-building foods, food
substances, energy producing foods, calcium, fats, phosphorous
3. Cube, regular solid, pyramid, cylinder, irregular solid
4. Liquids, chemical classification of matter, pure substances, compounds, mixtures,
solids, homogeneous mixtures, heterogeneous mixtures, elements, organic
compounds, metallic elements, gases, inorganic compounds, non-metallic elements,
physical classification of matter, matter
5. Chlorine, gases, hydrogen, visible gases, invisible gases, nitroge.

19. PRACTICE 4
Read the following paragraph and make a tree diagram:
Automatic computers may be broadly classified as analog or digital. Both analog and
digital computers include a subclass of rather simple machines that mechanize only
specific simple operations. For example, the slide rule is an example of operation-
only-machine of the analog type whereas examples of operation-only machines of the
digital type include adding machines and desk calculators.
A second class, more sophisticated than operation-only machines, may be termed
problem-setup machines. The electronic differential analyzer is the most general form
of analog computer in this group. The plugboard accounting machines and digital
differential analyzers are problem-setup digital computers.

20. Technical Communication
Assignment VIII
PRACTICE I
Study the following sentences and underline the markers of comparison! contrast. The
first one is solved for you.
1. The ionic bond involves charge attractions while the covalent bond involves sharing
electrons between bonded atoms.
2. Both the computer and the brain have a complex structure.
3. Low carbon steel contains between 0.08 % and 0.15 % carbon. On the other hand, mild
steel contains between O.15 percentage and O.35 percentage carbon.
4. Alkali metals form positive ions whereas the halogens form halide ions of negative
charge.
5. The power of the diesel engine is greater than that of the steam engine.
6. Digital differential analyzers are more sophisticated than desk calculators are.
PRACTICE 2
Read the following sentences and fill in the blanks with appropriate linkers to show
comparison/contrast:
1. A hot engine will run on a weak mixture ---------------- a cold engine requires a richer
mixture.
2. Water is made of hydrogen and oxygen -----------------carbon dioxide is made of carbon
and oxygen.
3. In nature, oxygen is found in the form of oxygen molecules.---------------, many other
elements exist in molecular form and not as free atoms.
4. Some elements are in molecular form ------------others are in atomic form.
5. The two machines ------------- are in many respects.

21. PRACTICE 3
Read the following passage and fill in the blanks:
In past scientists could produce simple compounds like Water, carbon dioxide, hydrogen
chloride or sulphuric acid in the laboratory…. 1…. , many molecules like urea or sugar found
in living organisms, could be synthesized. These compounds were found in living organisms.
….2…. , some scientists felt that the vitality of the living organism was necessary to form these
compounds….. 3…. , some other scientists did not like this explanation. The concept of
chemical affinity was proposed for explaining why some reactions take place…. 4….. others
do not. ….5…. , sulphur has an affinity for oxygen ---6--- no' affinity towards nitrogen.
PRACTICE 4
Study the following table and write a comparison/contrast using block organization:
Mainframe computers Micro-computers
. Expensive, large, centralized . Cheap, small
computer facilities . Called personal computers
. Multi-user computers . Single user devices
. A super computer connected to . Based on standard micro-
several terminals Processors
. Large memory and fast speed
(several millions of floating-
point operations per second)

22. PRACTICE 5
Study the following table expressing differences between plants and animals, and write a
paragraph using the information given in the table:
Use an appropriate Iogical pattern, i.e., Block Organization or Unit Organization
Plants Animals
Food Manufacture their own food Obtain food from plants or
other animals
Structure Plant cells are enclosed in a Animal cells are enclosed in a
non-living wall membrane
Locomotion No power of Locomotion Can move
Relation to environment Insensitive to their Sensitive to their environment
environment
Growth Growth throughout their lives Growth is limited to definite
time period

23. Assignment IX
PRACTICE 1
Read the following sentences and underline the theme and identify the cause in each
statement:
I. Open cast mining causes air and water pollution.
II. Much of the disappearance of the world's forest cover was concentrated in the
tropical and sub-tropical regions as a result of the clearance of forestland for
farming, the logging of tropical hardwoods, and firewood gathering.
III. Accidents in factories often result from ignorance of safety regulations.
IV. Famine can result from floods, droughts and poor harvests.
V. Deficiency of vitamin A can lead to night blindness.
VI. Deforestation of the earth continues unabated, reducing the capacity of soils and
vegetation to absorb and store water.
VII. Exposure to traffic fumes may result in lead poisoning.
VIII. The accumulation in the atmosphere of greenhouse gases generated by human
activities is altering the earth's climate
PRACTICE 2
Read the following passages and fill in the blanks with appropriate words/ phrases from
the list given in the table above:
I. The clock Big Ben needed repair---1--- it suddenly stopped working. The
engineers who repaired the clock believed that the breakdown was the ---2---
metal fatigues. Metals deteriorate ---3--- repeated stress above a certain critical
level. Part of the clock mechanism fractured. ---4---, the speed of the gear
wheels increased from 1.5 revolutions per minute to 16000 rpm. ---5---, the

24. centrifugal force threw pieces of the clock mechanism in all directions. It, ---6---,
damaged the mechanism which drives the clock's hands.
II. The oxidation of organic compounds during respiration liberates carbon
dioxide in the atmosphere and ---1---helps in maintaining the proper balance
of C0 2. The combustion of coal, oil and other fuels ---2--- enormous production
of C02 yet the percentage of C02 has remained nearly constant since it was
measured first. It is, ---3---, obvious that the total rate of C0 2 consumption during
photosynthesis just equals the C02 production on a global basis. It is this balance
which maintains the Earth's atmosphere If C0 2 is not utilized during
photosynthesis; its proportion in the atmosphere will definitely rise to a great
extent. ---4--- CO2absorbs infrared radiations; there will be an appreciable rise in
temperature. This may ---5--- the melting of polar ice caps and ---6-7--- floods
and ---8-- there will be a variation in the level of the oceans.
PRACTICE 3
Make sentences showing cause/effect relationships by using all the phrases given. The
phrases are not in the right order. Example:
Q: Carbon dioxide (C02) emissions from energy use, pollution
A: Carbon dioxide emissions from energy use causes pollution
I. acid rain, coal-based thermal plants, soil damage, gaseous missions as
II. sulphur di oxide, nitrogen oxide etc.
III. loss of production, conveyor belt, effect of breakdown
IV. Inhaling silica dust, silicosis
V. Stripping the land of valuable nutrients for crop growth, poor agriculture
practices soil erosion
VI. Chlore-flucarbons, depletion of the ozone layer, increases in the ultraviolet
ray intensity at the surface of the earth.

25. PRACTICE 4
Study the following information and write a paragraph using the information and
arranging it in logical order:
• Gaseous emissions as sulphur dioxide, nitrogen oxide, etc.
• Coal-based thermal plants
• Produces a tremendous amount of solid wastes, flyash and bottom ash.
• Acid rain.
• Damage soil, vegetation and aquatic life of the region.
• Corrodes plant and machinery.
• Pollutes the atmosphere

26. Assignment X
Practice 1
PRACTICE 2
Read the following passage and use a table to show the events with reference to time:
The ISRO space programme has come a long way from a modest beginning with the
Rohini soundingfollowing passage Nov 21, 1963. Space Science and Technology Centremake the narrative
Read the rockets launch on and supply appropriate forms of verbs in order to
(SSTC) was established in 1965 in printed inIt wasletters. to Sariharikota launching station
meaningful. The verbs are Thumba. bold shifted
in 1969. However, the first Indian setellite "Aryabhata" was launched from the USSR on
April 19, 1975. from around seven centuries ago, scientists were busy conduct experiments with a variety of
Starting It was followed by the second Indian satellite "Bhaskara-I" on june 7, 1979.
It was substances. They try to he satellite launchfor converting cheap the 36-kg Rohini
in 1980 that the ingeneous find a method vehicle(SLV-3) put and readily available metals of like lead
satellite into orbit fromprecious and range.
and copper into Sariharikota expensive gold. In these experiments, they try all methods they know -
mixing, heating and separating materials. They succeed in making gold. However, in the process, they
generate and carefully record a )e wealth of information, which help to develop our understanding of
nature.
The early experiments in chemistry consist only of mixing and heating substances at random. Later
careful quantitative measurements begin to make .Quantitative relationships of chemistry emerge, help
later scientists. For example, Dalton study the composition of several compounds. He find that no matter
which sample of a particular substance take, the proportion by weight of the elementary constituents
remain the same. He also find that the constituents combine in several ways to form different substances.
PRACTICE 3 the following:
He deduce
• All matter is and of very tiny particles (he called them atoms) which cannot be broken down
Study the following tablemade write a narrative paragraph about asteroids:
further.
Year • Firstatoms of an element are identical.
All about asteroids
1801 • The firstof elements can combine in several ways to form different substances.
Atoms asteroid discovered; numbered 1 and named Ceres.
1891 Asteroid number 323 is the first to be discovered by photography;
While Dalton’s theory explain many things and enable us to interpret several observations
named Brucia.
1977 (Complexity, law of2060- has combinations), it not explain everything. Dalton assume that the atom
Asteroid number chemical the most distant orbit; named Chiron.
1983 was not divisible . This pictureto be discovered by spacecraft; named 19th century. Just the twenty
Asteroid number 3200; first dramatically change at the turn of the
Phaethon.
year period from 1895 to 1915 change so many basic concepts related to atoms and reveal so many
1991 The first asteroid to be photographed by a space probe; named Gaspra.
new phenomena that mans understanding of the natural world undergo a radical change.
PRACTICE 4

27. Read the following paragraph, and fill in the blanks with appropriate expressions to
show the intended temporal relation:
---1--- a simple calculating machine known as abacus was developed. ---2--- John
Napier devised a set of rods in 1617, which could do calculations involving
multiplications. ---3-in
1642 the first mechanical calculator was made by Blaise
Pascal.---4---in 1671, a german mathematician Gottfied Liebnitz
modified Pascal's machine. ---5--- it was Charles Babbage who
developed a machine which could evaluate algebraic as under
expressions correctly up to 20 decimal places.

28. Practice 5
The following sentences form a narrative paragraph, but they are in the wrong order. Put them in the
right sequence.
A. In developing a technology, several scientific principles could be employed at once.
B. The electric generator and the electric bulb are examples of the application of the principles of electricity,
mechanical engineering, heat conduction and other aspects.
C. Newer and more complex applications became possible then.
D. As science advanced and became more prevalent, its applications also grew in number and in pace.
E. This caused a revolutionary increase in technological inventions.
F. The miner's safety lamp invented by Davy involves an understanding of the principles of heat
conduction, smoke escapement, light transmission and safety procedures.
PRACTICE 6
Read the following sentences and fill in the blanks with appropriate words (If / when / unless / until):
I. ---------------------------------a system in equilibrium is subjected to a stress (i.e., change of temperature,
pressure or concentration), the equilibrium shifts in such a way so as to undo the effect of the stress
imposed.
II.A body is said to execute a simple harmonic motion it moves with an acceleration which is proportional to
its displacement from its position of equilibrium and is directed towards it.
III. ----------------------------hydrides such as NaH are electrolysed, hydrogen is liberated at the anode.
IV. Two bodies are known to be in thermal equilibrium ---1--- there is no transfer of heat between them
---2--- they are put into contact.

29. Assignment VI
Write a short paragraph on the following: (100- 120 words)
1. Do not count your chicken before they hatch
2. A bird in hand is worth two in a bush
3. A new broom sweeps clean
4. A rolling stone gathers no moss.
5. Actions speak louder than the words.
Write a composition on the following topics: (300 words)
1. Importance of communication in the work field
2. Role of women in today’s world

30. Assignment VII
1. Assuming that you are the purchase officer of a particular firm place an order for the
following item with modern furniture mart, sadar bazaar, New Delhi-110008.
2. Prepare a tender for the construction of a 20 ft wide cement concrete road (16 km)
from Pilani to Chirawa for submission to the executive Engineer ( B&R) P.W.D.
Modi road. Assume that you are the civil engineer in Royal construction house, court
road, Bhiwani.
3. Write letters to promote the sales of the following items:
• A newly published book on ‘Petroleum Exploration” among university
teachers
• A duplicating machine among educational administrators, heads of
government offices and office managers of private business houses
• A body builder club among college students
• An automatic toaster among housewives.
4. (i) As a whole seller write a letter to the manufacturer telling him that the retailers to
whom you have distributed 800 sets of super fine pens have been complaining about
their quality. Say that you have advised the retailers not sell the remaining stock,
pending full investigation.
(ii) Reply to the above letter. Express regret, promise investigation and offer
replacement of the unsold stock. Ask for the addresses of the retailers to whom you
have complained and say that you will talk to them directly.

31. 5. Assume that you are the credit manager of a weekly magazine, readers Paradise,
published by Core communications private limited, Nasik. In response to an
advertisement offering Diwali gift subscriptions at a special low prize of Rs.500/-
per annum (instead of a regular subscription of Rs, 750/-) the firm has received 1500
orders. At the request of the prospective subscribers, the bills for payments have
been sent to them, demanding payment within 15 days. However you anticipate that
some of them will not pay on time. Write a series of collection communications
which you will use for obtaining payment. Invent the necessary details.

32. Assignment VIII
1. What is oral and written communication? Give the differences between the two.
2. What are the advantages and the disadvantages of both?
3. What do you mean by non verbal communication?
4. State how does a mans way of walking, standing, sitting reflect his position, state of
mind and feelings.

33. Assignment IX
1. What is listening? Explain the statement ‘listen not only with your years but also
with your eyes.’
2. In what ways is listening different from other passive skill reading. What techniques
would you suggest to enhance ones listening abilities.
3. Can listening as a skill be taught? What techniques would you suggest to enhance
ones listening ability.
4. some reading comprehension passages.